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■ 

MODERN 
ELECTRO PLATING. 



The Principles Involved in Depositing Gold, Silver, Nickel, Copper, Brass 
and Other Metals, by means of Batteries or Dynamos ; The Prepara- 
tion and Management of Plating Baths, Chemicals Used, Etc. 



BY J. H. VAN HORNK 









CHICAGO : 
GEORGE K. HAZLITT & CO. 

J897. 






A 



<° <* 



COPYRIGHTED BY 

Geo. K Hazlitt & Co. 

1897. 






INTRODUCTION. 



This little work has been prepared chiefly to help out 
of his difficulties the plater in country towns who has 
purchased a small outfit and begun operations without 
previous training in a plating establishment where mod- 
ern methods have been employed with a due regard for 
speed and economy in turning out the work. Hence it 
has been thought best to confine our remarks chiefly to 
the principles involved in the work, and to tell in a com- 
mon sense way, how the work is done; what forces are 
employed; how they are handled, and how the various 
formulae may be made and varied to suit the conditions 
of the work or to overcome the difficulties that may 
arise in continuous working of solutions. 

It has seemed better to do this than to give a large 
number of formulae which, although they may be per- 
fectly adapted to a special purpose, contain in them- 
selves no real information, but have to be taken blindly, 
like a physician's prescription for a fever. It must not 
be forgotten that the chemistry of plating has undergone 



4 INTRODUCTION. 

strict investigation in the last five years by thoroughly 
educated and competent men, who have found abundant 
opportunity for their labors in the many large plating- 
works now used in connection with manufacturing estab- 
lishments, where the finishing of the products is of the 
highest importance, and owing to the quantity of goods 
turned out any defect in the composition or management 
of the baths is of the highest importance. The labors of 
these chemists have been chiefly effective in eliminating 
from the formulae in common use those chemicals which, 
from their nature, were antagonistic to the chief ingredi- 
ents, or which by their decomposition left detrimental or 
inert matter in the solutions. As an instance of this we 
may mention the substitution of chromic acid for bichro- 
mate of potash in battery fluids; the purchase and use of 
the carbonate of copper and zinc in brass solutions 
instead of compounding them in the old way from the 
sulphates, etc. In all cases the effects of the alterations 
have been to simplify and greatly improve the keeping 
and working qualities of the solutions, and in many cases 
the improvement has been very great. These new 
methods of making solutions have been industriously cir- 
culated by the dealers in plating apparatus and supplies, 
until now the chief source of trouble in plating has 
shifted from the plating to the polishing department, and 



INTRODUCTION. 5 

while the chief difficulty formerly lay in the solutions, 
nine out of ten cases of trouble now may be traced to the 
improper preparation of the work before it reaches the 
bath, or to careless and hasty finishing after it has left it. 
Therefore, it has seemed better to deal with the opera- 
tions of plating in a general way, detailing the principles 
involved, and allowing the operator to make his own 
baths from general directions, rather than to follow the 
empirical methods formerly employed, which gave no 
hint of the source of any difficulty, and left the plater 
unable to help himself when trouble was encountered. 

It will be readily seen from the above remarks that 
plating has been stripped of about all the mystery that 
formerly surrounded it, to the great chagrin and vexation 
of a certain class of workmen who formerly found an 
easy way of getting an income by the sale of certain 
very important and mysterious formulae, without which, 
they solemnly assured their intended victim, good plating 
could not be done. In fact, it is now generally rec- 
ognized that good, durable plating depends chiefly 
upon the degree of care and skill employed in the appli- 
cation of well known methods of doing work, while the 
question of profit depends altogether upon the personal 
dexterity of those who do the work, and a rapid and 
skillful plater holds the same relation to his fellow 



6 INTRODUCTION. 

employes that a rapid and skillful machinist does in his 
trade. 

With this explanation we think the reader will suffi- 
ciently grasp the scope and purpose of this work. It 
does not pretend to teach everything, but only to prove 
useful in aiding the workman to a general understand- 
ing of the subject which will enable him to consult other 
books intelligently, or to help himself where other 
guidance is not available. 

The little pamphlet. " Practical Points on the Deposi- 
tion of Metals," which was the first attempt to give 
practical information in a general way has been so 
warmly received that it encourages me to hope that 
more on the same subject will be appreciated by those 
who are desirous of acquiring skill in the art of plating. 

J. H. VAN HORNE. 



CHAPTER I. 



THE MANAGEMENT OF BATTERIES, 

The first requisite in attempting to do electroplating 
in a small way is to understand the battery and to select 
one that will give an electric current of the proper 
intensity and quantity for the required time, without too 
much care and attention on the part of the workman. 
Were he provided with measuring instruments, so that 
he could readily determine when his current was chang- 
ing in quantity and power, the choice of a battery would 
not be of so much importance; but volt meters and 
ampere meters are too expensive to be possessed by the 
average man who does plating in a small way, and he is 
necessarily obliged to depend on theory in arranging his 
forces and judge of the results by the appearance of his 
work in the bath. Hence it is important that he should 
have an understanding of the nature of the action in the 
battery and be able to maintain the requisite conditions 
from the appearance of the battery itself. 



O MODERN ELECTRO PLATING. 

Electricity. — Without attemping to give too close a 
definition, electricity may be defined as a force or 
energy which is the result of a displacement of the 
normal balance of forces between two elements con- 
nected with one another by a conducting medium. 
This difference in the balance of force is called the 
potential of its elements and if two elements having 
different potentials, are connected together and placed 
in a fluid which will produce chemical action upon one 
or both, the result will be a flowing of energy through 
the connection to the element having the lowest poten- 
tial. This will be kept up as long as the chemical 
action continues and the connection between the two 
elements remains unbroken. It will be readilv seen, 
that owing to the varying potentials of the different 
elements, the varying facility of the conductors used to 
connect them, and the varying intensity of chemical 
action in the solution employed, the electrical current 
will vary in strength (or voltage) in different batteries, 
and in quantity, according to the size of the elements 
and the freedom with which they are attacked by the 
solution. 

Voltage is the measure of strength or intensity of the 
current and depends upon the difference of potentials of 



MODERN ELECTRO PLATING. 9 

the elements and the kind of chemical action between 
them. It is the same for the same combination, regard- 
less of the size of the elements. Thus, a battery the 
size of a thimble has the same voltage as one the size of 
a door, if the elements and solution are the same. We 
have not the space to explain this at length, but will 
simply state that the volt is the recognized unit of the 
measurement of strength of electric currents. 

The Ampere is the unit of measurement of the 
quantity of currents. Amperage depends on the size 
of the elements; and the available amperage depends on 
the size of the conductors and the freedom of action 
between the elements. Amperage is consumed by 
doing work, or by the heating of insufficient conductors, 
or by undue resistance in the battery, just as power is 
consumed in turning steel, or in running shafting, or 
overcoming the resistance caused by friction of boxes on 
a shaft that is run without oil. Strictly speaking, if the 
voltage or intensity of the current be sufficient to do 
the work required, then the amperage is the force used 
to do the work, and it is destroyed by that work and 
the chemical or electrical resistance, just as mechanical 
power is consumed in running a lathe or doing any other 
work. From this, it follows, that in order to operate 



IO MODERN ELECTRO PLATING. 

•economically, extreme care should be taken that the 
connections be large enough to carry the current easily; 
that the solutions be kept in perfect order, both in the 
battery and the plating vat; and that all joints be kept 
bright and firm so as to insure perfect contact and offer 
no resistance to the passage of the current. 

The current always flows from the element having 
the highest potential (called the + or positive pole) 
along the wire and through the solution in the plating 
vat, to the other wire, and thence to the negative pole, 
carrying with it in passing through the solution, particles 
of metal from the anode and depositing it on the article 
to be electroplated (called the cathode); hence care 
should be taken to always get the cathode affixed to the 
negative (■ — ) pole of the battery, in order that it may 
receive the deposit. 

Electrical Resistance is that property of conductors 
(wires, solutions, objects, etc.) by which they tend to 
reduce the intensity of a current passing through them. 
The practical unit of resistance is the ohm. The num- 
ber of amperes of current flowing through a circuit is 
equal to the number of volts of electro motive force, 
divided by the number of ohms of resistance in the 
•entire circuit, that is from positive pole clear through 



MODERN ELECTRO PLATING. II 

wires, solution and battery, back to the starting point. 
Thus it will be seen that if the resistance be greater 
than the voltage of one cell will overcome, no current 
will flow, and the voltage must be increased to such an 
amount as will allow the desired quantity of current to 
pass. This is done by coupling cells in various ways, 
which will be explained at length further on. 

The resistance of a conducting wire is directly pro- 
proportional to its length, and inversely proportional to 
the square of its diameter; hence it follows that the 
short and large wires cause less loss of current than 
smaller and longer ones. 

In all batteries the resistance increases with the dis- 
tance between the elements, and decreases when the 
immersed surfaces are increased. The resistance is also 
increased by the bubbles of hydrogen liberated at the 
positive pole sticking to it in great numbers. Hydrogen 
is a non-conductor and prevents the action of the solu- 
tion on the metal. When this takes place to such an 
extent as to stop chemical action altogether, no current 
will pass and the battery is said to be polarized. 

These remarks are intended to aid in the intelligent 
selection of batteries, etc., those who, having to deal 
with such apparatus, yet have never had the opportunity 
to study an electrical treatise. We are often asked. 



12 MODERN ELECTRO PLATING. 

What is the best battery? We can only answer: There 
is no best battery; that is, no battery is suited to all kinds 
of work. That which is best in one case may be worst 
in another. The suitability of a battery for any special 
purpose depends on what is called its constants, i. e. ? 
electro-motive force and internal resistance. In order 
to be really perfect a battery should fulfill the following 
conditions: 

i. Its electro-motive force should be high and con- 
stant. 

2. Its internal resistance should be small. 

3. It should give a constant current and must'there- 
fore be free from polarization, and not liable to rapid 
exhaustion, requiring frequent renewal of material. 

4. It should consume no material when the circuit is 
open. 

5. It should be cheap and of durable materials. 

6. It should be manageable and, if possible, should 
not emit corrosive fumes. 

No single battery fulfills all these conditions, how- 
ever, and, as we have already intimated, some batteries 
are better for one purpose and some for another. Thus, 
for telegraphing through a long line of wire, a consider- 
able internal resistance is of no great consequence, as it 
is but a small fraction of the total resistance in circuit. 



MODERN ELECTRO PLATING. 



13 



For electric gas lighting or other low resistance circuits, 
on the other hand, much internal resistance would be, 
if not absolutely fatal, certainly a positive disadvantage. 
The most reliable batteries for electroplating work are 
the Daniell, Gravity, Bunsen, Smee and Carbon, which, 
we will accordingly describe in their order. 



The Daniell, Fig. 1, consists of a glass or stoneware 
jar, containing a cylinder of copper surrounding a porous 
clay cup, in which stands a 
cylinder of zinc. At the upper 
part of the copper sheet is a 
pocket of perforated copper, 
which is filled with crystals of 
sulphate of copper. The ob- 
ject of the pocket is simply to 
hold the sulphate up to the top 
of the solution, so that it will 
dissolve more readily, and any 
other method would do as well. 
In charging this battery, the 
glass vessel and the porous cup are filled with water, 
and crystals of sulphate of copper are put in the pocket. 
If wanted for immediate use, a small quantity of sulphate 
of zinc may be dissolved in water and added to the 




Fig. 1. 



14 MODERN ELECTRO PLATING. 

porous cup; if not wanted immediately, the battery may 
be short circuited by connecting the zinc and copper 
elements by a piece of copper wire, and it will attain its 
full strength in ten or twelve hours. A little sulphuric 
acid dropped in the porous cup will answer just as well. 
if sulphate of zinc is not on hand. The chemical action 
of this battery is as follows: The zinc decomposes the 
water, forming oxide of zinc and liberating the hydro- 
gen. The oxide of zinc attacks the sulphate of copper, 
depriving it of the acid, which fcrms sulphate of zinc, 
and leaving it as oxide of copper; the oxide of copper 
is thereupon attacked by the hydrogen, which combines 
with the oxygen and forms water, while the metallic 
copper falls to the bottom as a fine powder. It will 
thus be seen that action is simple and continuous, no 
fumes are given off, and all that is required to maintain 
the action is a regular supply of copper sulphate to 
keep the fluid in the outer jar, near the point of satu- 
ration. The most prominent fault of this battery is the 
tendency of the copper to rill the pores of the cup, and 
thus decrease the action of the battery. It can be par- 
tially prevented by coating the bottom and about a 
quarter of an inch of the sides of the porous cup with 
wax, and brushing off the deposit of copper on the cup 
as fast as it is formed. The battery should not be 



MODERN ELECTRO PLATING. 1 5 

allowed to stand on open circuit without the zinc ele- 
ment being removed, and the sulphate of zinc solution 
in the cup should not be heavier than 25 B. nor lighter 
than 15° B. If these precautions are observed, the 
battery should give a constant and free current as long 
as any zinc remains. Its electro-motive force is about 
1.07 volt, and a gallon cell will give about one-half 
ampere, when in good order, on a short circuit. Its 
internal resistance varies, but should not be allowed to 
exceed three to five ohms. 

The Gravity Battery, In consequence of the trou- 
ble caused by the precipitation of the copper on the 
porous cell in the Daniell battery. Cromwell F. Varley, 
in 1854, while experimenting, found that the difference 
in specific gravity between solutions of sulphate of cop- 
per and sulphate of zinc was sufficient in itself to entirely 
separate them, the copper solution lying at the bottom 
of the cell, and the zinc solution remaining superposed 
upon it. He accordingly dispensed with the porous 
cup, placed his copper element at the bottom, and the 
zinc near the top of a glass jar, and thus originated the 
gravity battery of today, It is the simplest, most relia- 
ble and constant form known, and has displaced all 
others for closed circuit work, requiring a low voltage. 



i6 



MODERN ELECTRO PLATING. 



such as telegraphing, etc. Its voltage, when first set up. 
is 1.07, running down under constant work to .90, and a 
gallon cell will give one half ampere on short circuit. 
The form of cell shown in Fig. 2 is known as the 
"crowfoot," on account of the manner in which the zinc 
'(positive) element is spread out, to expose a large sur- 
face of zinc to the solution. It is the form used for 
telegraphing, and, therefore, can be 
readily obtained any where. Of 
course, other forms, shapes and 
sizes can be made at the option of 
the workman. To set up this bat- 
tery, the copper strip, being un- 
folded so as to form a cross, is 
placed at the bottom of a jar, the 
zinc is suspended from the top as 
shown, and clean water, containing one-tenth of a satu- 
rated solution of sulphate of zinc is added, until it nearly 
touches the zinc. Sulphate of copper crystals are then 
added until, if the battery is meant to be continually 
used, they nearly cover the top of the copper strip. If 
the battery is not intended for continual use, it will be 
found more advantageous to use but a few ounces of 
sulphate of copper, as the more concentrated the solu- 
tion, the greater is the tendency to local action. The 




MODERN ELECTRO PLATING. 1 7 

sulphate of zinc may be dispensed with if the battery is 
not required for immediate use; in this case, the latter 
should be short circuited, and left so for several days. 
The need of blue vitriol will be indicated by the dis- 
coloration of the lower stratum of the liquid. It is best 
to keep the line marking the two solutions about half 
way between the zinc and copper. Should the sulphate 
of zinc become too concentrated, a portion of it should 
be removed by means of a syringe qv cup, and its place 
supplied by water. To determine when this is neces- 
sary, a hydrometer may be used. Below 15 the solu- 
tion is too weak; above 25 it is too strong, and should 
be diluted. If the battery is taken care of from month 
to month, it should not require a thorough cleaning 
more than once a year. When this is done the deposits 
formed upon the surface of the zinc should be scraped 
off, the jars washed and the liquids renewed as in the 
beginning. 

If, however, the batteries are in constant use, care 
must be taken to keep the zincs clean and the solutions 
as indicated above. If the sulphate of zinc is allowed 
to become saturated, it will crystalize on the zinc and on 
the edge of the jar, gradually creeping over the edge. 
This should be wiped off with a damp cloth and a little 
oil or fat smeared over the top of the jar to prevent 



iS 



MODERN ELECTRO PLATING. 



creeping. The jars should not be disturbed, as this 
would cause the two solutions to mix, and they should 
be kept in a dry, even temperature (6o° to 8o c F.). 
Freezing would stop the action of the battery. 



The Bunsen, or Carbon Battery, Fig. 3, consists 
of a glass jar containing a hollow zinc cylinder, slit 
on one side to allow a free circulation 
of the solution; within this stands a 
porous cup containing a bar of carbon. 
To charge this battery, the amalga- 
mated zinc is placed in the glass jar,, 
the porous jar in the center of the 
zinc cylinder and the carbon in the 
porous jar. In the outer jar is sul- 
phuric acid, diluted with twelve times 
its weight of water, and in the por- 
ous jar electropoion fluid. (See Electropoion Fluid.) 
The voltage of this battery is 2.028; its amperage 
cannot be given, as it depends largely upon the care 
which is given the battery, the size of the cell and the 
condition of the porous cups, which vary greatly in 
porosity and conducting power. It emits fumes of 
hydrogen and sulphurous acid if not in good conditiom 
and should not be used in the same room with line tools 




Fig- s- 



MODERN ELECTRO PLATING. IQ 

or metal work that is liable to injury. It soon runs 
down, requiring recharging every day when in constant 
use, but it is simple to handle when understood, and is 
generally furnished in small outfits for nickel plating, 
etc., on account of its high voltage and the quantity of 
current given off when in good order. The zincs must 
be kept well amalgamated or they will polarize very 
rapidly and destroy the current; care should also be 
taken that no sediment be allowed to accumulate in the 
porous cup and fill its pores, thus stopping the action. It 
is more expensive to run than the gravity, as the zincs 
are eaten by the acid much faster, especially if not kept 
well amalgamated; but it will deliver a greater quantity 
of current in a given time than a gravity cell of equal 
size. The internal resistance of a new cell is about one- 
half an ohm. The plates should be removed and 
cleaned when the battery is not in use. 

The Smee Battery, Fig. 4, consists of two plates 
of amalgamated zinc, between which is placed a silver 
plate coated with platinum, the object of the platinum 
being to fill the surface of the plate with innumerable 
fine points which aid in discharging the bubbles of 
hydrogen, which would cling closely to it if the plate 
were smooth and thus polarize the battery. This 



20 



MODERN ELECTRO PLATING. 



battery is charged with a solution of one part sulphuric 
acid to seven of water. The plates are connected to 
the clamp and placed in the jar. In this battery, above 
all. the precaution of amalgamating the zinc should 
never be neglected. With an unamalgamated zinc the 
results are very unsatisfactory. 

The voltage of the Smee, when not in action, is 1.09 
volts; when in action it runs down to .482 
volts; this is caused by the hydrogen 
clinging to the plate as described.' This 
was the form of cell generally used be- 
fore the introduction of dynamos for 
electrotyping and other heavy work, and jj| 
it is still used to a large extent. It 
emits fumes of hydrogen when in action, 
but it is a single fluid battery and when 
working in large sizes, plates 12x12 inches in size are 
suspended in a large tank of acidulated water, first a 
plate of zinc, then a plate of platinized silver, then 
another of zinc and so on alternately, zinc and platinum, 
to the end. This gives great facility in handling, as 
any number of plates to suit the work may be placed 
in the tank. As there is but one tank and the plates 
may be placed close together or far apart as required, 
the resistance may be easily made to balance that in the 




Fig. 4. 



MODERN ELECTRO PLATING. 21 

depositing tank, and thus the work will be performed 
under the most favorable conditions. 

In working the Smee, or any battery for that matter, 
large tanks are better than small ones, provided that the 
plates are kept close together so as to reduce internal 
resistance of the battery. In the large Smee, if plates 
12x12 are worked in a tank say 15x15x30, it will not be 
long before the sulphate of zinc, which forms and falls 
to the bottom, will soon commence to rise in the tank, 
thus shutting off the acid from a portion of the plates 
and reducing the quantity of current. If the same plates 
were worked in a tank 24x24x30, the tank might be 
permitted to become half full of zinc sulphate before 
the action would be impaired at all, and thus a much 
more even and constant current would be maintained; 
this is generally done in practice. In a gravity battery, 
however, the tank ought not to be deep, because the 
two elements should not be more than eight inches 
apart on account of the increased resistance caused 
by the separation. The tank, however, may be large 
enough in length and width to contain elements of 
the desired size, or a number of standard zincs and 
coppers, if such an arrangement seems desirable, either 
to increase the facility of handling or reduce the cost 
of a large number of jars, wires, connections, etc. We 



2 2 MODERN ELECTRO PLATING. 

have seen a number of tanks made of wood, lined with 
lead, 10x10x60 inches, in which a single large copper 
element was placed at the bottom and a number of 
zincs hung as required from an insulated copper bar 
across the top. It seemed to work well and was con- 
venient. 

Varying. Strength of the Current by Coupling. 
A few words as to coupling batteries may be of 
service. It should be borne, in mind that the quantity of 
current flowing in any circuit is the quotient resulting 







Fi s . s . 

from dividing the voltage by the total resistance in that 
circuit and that the resistance may be increased or dimin- 
ished by increasing or diminishing the distance between 
the elements of the battery and between the anode and 
cathode in the plating vat; also that the resistance varies 
inversely, as the surface of the elements immersed. 
Thus a plating surface of one square foot in the plating 
vat will offer four times as much resistance as four 
square feet. It thus becomes possible by increasing or 



MODERN ELECTRO PLATING. 23 

diminishing the voltage of a current to keep the current 
flowing in the desired quantity, and by keeping the 
resistance in the battery about equal to that in the vats 
the highest economy is obtained. 

For example, let us take eight cells, having a voltage 
of 1, and giving say y 2 ampere per cell on short circuit. 
If we now couple them — , ■+ , — , +, — , +, — , +, we shall 
have the voltage of 8 and the amperage of one cell of 




— Q 

Fig. 6. 

the same size, in other words, the same amount of cur- 
rent and eight times the strength of the single cell, as 
in Fig. 5. 

This is termed coupling in series, and would be used 
in solutions having a high resistance and small amount 
of surface immersed. If, on the other hand, the solu- 
tion had a low resistance and large surface exposed, so 
that the voltage of one cell was ample to force the cur- 
rent through the circuit, they should be connected +, +, 
+> +j + 3 +, +, +, and — , — , — , — , — , — , — , — , giving 



2 4 



MODERN ELECTRO PLATING. 



the quantity ot eight cells and the voltage of one, which 
amounts to nearly the same thing as if a single battery 
having eight times the surface of the single cell were 
used. This is termed coupling in multiple, Fig. 6. 
Similarly, if they were coupled +, — , +, — , +, — , +. 
— and +, — , +, — , +, — , +, — . and those two were 
joined as in Fig. 7, we should have the equivalent of a 
battery possessing a voltage of four. 
c and elements twice the size of the 
single cell. This would be spoken 
of as a battery of eight cells in series 
of four. Also four multiples, in series 
of two, might be arranged to give 
a voltage of two and quantity due to 
cells of four times the size of a single 
cell, as shown in Fig. 8. As the 
amperes of current passing per sec- 
ond depends upon the voltage, divided 
by the number of ohms resistance, in the circuit, it will 
seen that the current can be controlled by coupling 
and by manipulating the resistance. 




Fig. 



To Amalgamate Zincs. This may be very well 
done by first immersing the zincs in a solution of dilute 
sulphuric acid and then in a bath of mercury. A brush 



MODERN ELECTRO PLATING. 



2 5 



or cloth may be used to rub them, so as to reach all 
points of the surface. Where a large quantity is to be 
amalgamated, the following will be found to be a good 
method: Dissolve eight ounces of mercury in a mixture 
consisting of two pounds of hydrochloric and one pound 
of nitric acid; when the solution is complete, add three 
pounds more of hydrochloric acid. The zinc is amalga- 
mated by immersing it in this solution for a few seconds, 
quickly removing to a vat of clear water and rubbing it, 
as in the first case, with 
a brush or cloth. If the 
solution is kept in a 
covered vessel it may be 
used a number of times. 

In all batteries in c ~ 
which acids are used the 




Fig. 8. 



zincs should be kept well amalgamated and should be 
removed from the solution when not in use. This is 
very important and should not be overlooked. 



Improved Electropoion Fluid* Add one part (by 
volume) of sulphuric acid to ten parts of water. Of 10 
pounds (or pints) of the dilute acid, add from 1 to 2 
pounds of chromic acid, according to the strength of cur- 
rent desired. Where constant action over a long time 



26 MODERN ELECTRO PLATING. 

is desired rather than maximum energy, omit part 
or all of the sulphuric acid. 

Bichromate of potash is no longer used for batteries 
by intelligent workers. It owes its virtues to a small 
amount of chromic acid which can be obtained from it by 
reaction. Pure chromic acid is cheaper for the same 
work, and is free from many of the difficulties attendant 
on the use of the bichromate. 

Connections. Having a knowledge of the theoreti- 
cal action of the battery, the next question is the con- 
nections. Cleanliness cannot be too strongly insisted 
upon in making joints, etc. The plater should make it 
an invariable rule to see that all surfaces of wires, 
screws, etc., through which the current must pass, be 
kept bright on the surfaces through which electrical 
contact is made. When joining wires they should be 
brightened with a file, or with emery cloth, and then 
twisted firmly together with a pair of pliers; all perma- 
nent connections should be carefully soldered and the 
holes and the ends of screws in binding posts should be 
kept bright; and if for permanent use all conducting wires 
should be of pure copper, well insulated. The following 
table shows in the last column the loss of current in wires, 
carrying an economical amount of current; if the 



MODERN ELECTRO PLATING. 



27 



wire be too small this loss is rapidly quadrupled until 
the wire burns. The economy of using large and short 
connections will be apparent after a slight study of this 
table. 

Table showing the Weight, Carrying Capacity and Loss in 
Volts of different sizes Copper Wire. 



a 

1- 

d 

S at 
g'JJ 



OOOO 

OOO 

00 

o 

I 

2 

3 
4 
5 
6 

7 
8 

9 
10 
11 
12 
13 
14 

15 
16 

17 
18 



o a 
Ha 






46 

40964 

•3648 

•32495 

.2893 

•25763 

.22942 

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CHAPTER II. 



DYNAMOS, CONNECTIONS AND TANKS. 

In the past, platers have been obliged to depend upon 
the battery in a great measure. This has often been 
found an unreliable source of energy. It is at the same 
time an expensive source of current, consuming valuable 
chemicals and costly metals, and giving a comparatively 
small return in current. Again, the battery for plating 
is objectionable on account of the mercury that is used 
to amalgate the zinc. Mercury is the worst enemy to 
the electro-plater, it always being ready, even in the 
smallest particles, to amalgamate with his finished work 
and make black spots that cannot be removed except 
by re-plating. Fumes of acids used in the battery fre- 
quently cause annoyance and damage. It has been due 
to the above difficulties that the chemical battery has 
never come into general use, only being used when no 
other source of electrical energy could be obtained. 
When batteries are used, and the work does not come 



MODERN ELECTRO PLATING. 



2 9 



out right there are several places to which the plater has 
to look for trouble. First, to the condition of the solu- 
tion; then the plates, and then the acid-destroyed con- 
nections and contacts. With the use of a dynamo the 
operator at once has a reliable current, costing nothing 
when in idleness, except interest upon investment, and 
when in operation but a little for power. 

The question of power is often one of the principal 
obstacles to the use of a dynamo. If you have no power 
in your shop, and no way of getting it, a dynamo can- 
not be used, and in this case batteries will have to be 
coupled together and enough of them used to take the 
place of a dynamo. 

If power is available, it would be a false economy to 
use anything but a dynamo. The original cost is more, 
but the facility for doing work is greatly increased; 
there is then no variation in current, and a dynamo 
requires practically no attention. 

A dynamo depends for its current upon the fact that a 
copper wire, passed between the poles of a magnet, will 
generate a current of electricity in the wire; this cur- 
rent bears a definite relation to the strength of the magnet 
and the number of times the wire is passed between the 
poles. From this it will be seen that the size of wire, 
the strength of the magnet and the speed of revolution 



3Q 



MODERN ELECTRO PLATING. 



all have a bearing on the current produced and that by 
altering the various factors given above we can obtain 
the quantity and strength desired. Before dynamo 
building had attained its present state of advancement, 
great difficulty was experienced in producing currents of 
low voltage by this means, and the older dynamos were 




•i Modern Dynamo. 



very apt to burn the work; hence the notion, still held 
by many old platers, that the dynamo is unsuited to do 
really hard and durable plating. This is completely 
overcome in the modern dynamo and the much lower 
speed of the modern dynamo makes them at the same 
time less expensive to run and more durable and longer 
lived. Therefore the plater who is tempted to buy a 
second-hand machine, on account of its low price, may 



MODERN ELECTRO PLATING. 3 1 

find it the most expensive machine he could use, and be 
finally obliged lo throw it away and get something up to 
date in order to get the cost of producing work down to 
a figure that will leave him any margin at all. When 
buying a dynamo, see that it is a modern machine. 

See that it will do your work. 

See that it does all that is claimed for it. 

See that it does not require constant attention. 

See that you get a constant, steady current. 

You want a machine that will not spark. 

You want one in which you can control the current. 

You want one that will not reverse, or heat. 

You want one that is noiseless. 

Get one that is not overestimated in capacity. 

Get one having all parts interchangeable. 

Get one that when taxed to its utmost capacity will not 
drop its current. 

Dynamos and motors capable of giving the best 
results for a short time may be constructed with very 
little regard for mechanical principles. In selecting a 
dynamo or motor, the fact that the machine is to be used 
for many years, under heavy strain and subject to little 
attention, should not be overlooked. Its continued elec- 
trical efficiency is dependent on a high order of mechan- 
ical excellence. 



32 MODERN ELECTRO PLATING. 

Setting up and Running* The dynamo should 
rest on a solid or substantial foundation as near to the 
tanks as convenient, and be placed at a height that will 
give your plater easy access to all its working parts, 
especially room to set or adjust brushes, as a few min- 
utes' attention each morning adds greatly to its effici- 
ency, and keeps commutator and brushes in good con- 
dition. 

See that the dynamo rests firmly on its foundation, as 
absence of vibration adds to the life of the machine and 
insures a more uniform current. 

Set the brushes so that they come in contact w r ith the 
commutator both top and bottom so as to be directly 
opposite. To avoid sparks, keep brushes beveled, and 
avoid letting under leaves drag. Carefully adjust the 
brushes without too great pressure, to insure perfect 
contact between brush holder and rod. Too hard pres- 
sure will cut the commutator. The brushes are fur- 
nished beveled, and can be kept so by riling. Occa- 
sionally the projecting part or end of top leaf can be 
trimmed. A little care in adjusting brushes so as to get 
the bevel resting squarely on the commutator will pre- 
vent sparking. Sparking at the brushes does not neces- 
sarily indicate a fault in the armature. It is more pro- 
bably due to imperfect adjustment. To remedy, move 



MODERN ELECTRO PLATING. 33 

the rocker arm back and forth, and if the sparking does 
not entirely cease, alter tension of brushes, See that 
they bear on comutator the full curve of brush face. 
There is but one non- sparking point, and after the rocker 
arm is adjusted to this, do not move it. It is not 
intended to regulate the current or speed. Lubricate 
the commutator with vaseline and plumbago mixed and 
apply with a piece of hard felt. If commutator shows 
signs of roughness, smooth it with a piece of fine sand 
paper, and then lubricate. Never use emery cloth or a 
file. If badly roughened, take armature out and turn 
commutator off in a lathe. It is a mistaken idea that 
brushes must bear hard on commutator. Only pressure 
enough to preserve good contact is required. The com- 
mutator, to be in perfect condition, should glaze over 
and show no appreciable wear. It may be kept so by 
skillful handling of the dynamo. When the commuta- 
tor once becomes glazed, it is an indication that the 
brushes are in the right position, and it will not require 
sandpaper for months; simply use the oil and plumbago. 
One man should have charge of the dynamo and be 
held responsible for it. 

Connections* The matter of battery connections has 
been fully covered in the article on primary batteries 



34 



MODERN ELECTRO PLATING. 



and the method of connecting the battery and tank for 
small work will be fully understood by reference to Fig. 
10, while the importance of the size of wire used for 
conductors, etc., is fully detailed in the table on page 27. 
The arrangement and size of connections for dynamos 
in larger shops, using a number of tanks, is, however, 




Fig. 10. 



a very different matter. Here the plan is to use two 
large conducting bars running from the dynamo past 
the various tanks and to take the current from these 
bars by means of wires or rods leading to the various 
tanks. False economy is often practiced here and, as 
usual, it leads to trouble. One instance will be sufficient 
to explain what is meant. An electrotype foundry pur- 
chased a dynamo when starting in business, and, object- 
ing to the cost of solid copper bars of the size pre- 



MODERN ELECTRO PLATING. 35 

scribed by the dynamo manufacturer, used large brass 
tubing instead. Everything went well until business 
grew so much as to completely fill the tank with work, 
when they found that they could not deposit the copper 
in the required time. Naturally they thought they 
needed another machine; the old one was not up to its 
rated capacity, etc., etc., and the salesmen of various 
dynamo builders looked solemn and tried to sell them a 
machine to replace the first one. One day the agent of 
the first one happened along, heard the story and calmly 
said: "You don't want another machine. Get your 
new solution into your new tank and come along 
with me, while / buy the conductors and you -pay for 
them." It was done; the agent bought i^ inch solid 
copper rods to replace i^ inch brass tubes, and the 
dynamo thereupon deposited the copper within the 
required time with both tanks full of work, while with 
the tubes as conductors it had failed to do it with one 
tank full. This will give an idea of the importance of 
putting a little money into copper when it is called for 
in the plating room. The expenditure occurs but once 
and it should be ample at the beginning. Take the 
advice of the dynamo builder in regard to the conductor 
bars for his machine. It will cost you money if you 
don't. 



36 MODERN ELECTRO PLATING. 

The bars should be put up in such a way that things 
cannot be hung upon them or fall across them. Unless 
this is done there is a constant temptation to the work- 
men to hang wires, hooks, etc., upon them, and short 
circuits will be frequent. When this is the case the 
entire force seems to get rattled and blind. A large 
plating establishment had a large nickel tank, copper 
tank, and a small brass tank all go wrong suddenly 
one morning. Do what they would, they could not 
find the trouble. They telephoned to a dealer and 
asked for an expert. He listened to the details and said: 
'• You don't want me up there; you've got a short cir- 
cuit somewhere; find that and you'll be all right." At 
two o'clock they telephoned again. He must come out 
there. He went, and the first thing he saw on entering 
the room was an iron crowbar leaning against the main 
conductor bars, ten feet from the dynamo. That crow- 
bar cost the wages of ten men for half a day. Short 
circuits are expensive. They have also been caused 
by fastening the conductors to damp walls without any- 
thing between the wall and the conductor. 

All permanent connections from the conductors to the 
tanks should be soldered when possible, as it obviates 
the necessity of keeping a constant watch on all joints, 
which must be done when screw clamps are used. 



MODERN ELECTRO PLATING. 



37 



Regulation of the Current.— When the dynamo is 
employed on several tanks at once the current must be 
regulated for each by interposing a resistance switch 
between the conductor and tanks. This is always put in 
on the positive bar and connected with the positive bars 
of the tanks. Fig. n illustrates such a switch. 

In using switch boards or rheostats, they are put up as 




Fig. u. 



near the tank as possible. The switch should rest at W, 
or weak point, while putting work into the tank, and 
should then be turned towards the strongest point until 
suitable current is obtained. These resistance coils are 
used to prevent " burning" the work, as if burned the 
deposit becomes brittle and very hard to polish. Where 
several solutions are required separate switch boards 
should be used with each tank. 



38 MODERN ELECTRO PLATING. 

All platers understand that different voltages are 
required to operate successfully different kinds of solu- 
tions, and that when a sufficient voltage is to be gener- 
ated for a solution of the highest resistance, and at the 
same time utilized in low resistance solutions, the tank 
nearest the dynamo, with the customary method, 
receives the most current, and a tendency to burn and 
blacken is noticed to a marked degree. When metals 
such as silver and copper are to be deposited in connec- 
tion with such metals as nickel and brass, a higher elec- 
tro-motive force is required, and considerable drop in 
voltage is demanded in the lower resistance solutions, so 
as not to blacken the work. 

Measuring Instruments are often a necessity in 
studying the conditions under which work is done, and 
if used will save their cost every month in any large 
establishment by enabling the plater to know exactly 
what quantity and strength of current he is using. This 
is especially true of mixed solutions for the deposition of 
more than one metal, such as brass, bronze and other 
alloys. Even on single solutions they are frequently of 
great service. The observing, practical electro-plater 
will know that the character of a deposit obtained in a 
certain solution with a definite area of objects to be 



MODERN ELECTRO PLATING. 



39 



plated, depends largely upon the reproduction of certain 
conditions, and especially upon the tension of the current 
for the certain area to be plated. To reproduce such 
conditions it is highly important that either the electro- 
motive force existing between anode and cathode, and 
the current flowing through the same, be accurately 




Voltmeter. 



determined in order that they may be reproduced at will. 
The ordinary galvanometer is insufficient and often mis- 
leading, and not at all satisfactory for the actual meas- 
urement of either the voltage or current; it indicates 
only a change of polarity. If it is desired to measure 
actually the E. M. F. existing at the terminal of the 
dynamo or bath, only the very best voltmeters or 
ammeters should be used. They should be so con- 
structed as to indicate quickly and accurately any" 



4° 



MODERN ELECTRO PLATING. 



sudden changes in current, and should be direct reading 
in volts and amperes, and their indications should not be 
subject to gradual changes. A sensitive voltmeter will 
indicate the slipping of belts, short circuiting in tanks, 
and any irregularities of power. The general acknowl- 
edgment of the absolute necessity of these measuring 




Fig. i3.—Atnfiere meter. 

instruments has increased the demand to such an extent 
that they are now quite reasonable in price. 

Whilst it will be sufficient in most cases to use a volt- 
meter in combination with a rheostat for regulating pur- 
poses, it will sometimes be found desirable to determine 
the actual amount of current in amperes passing through 
a tank. It is a fundamental law of electrolysis that a 
certain number of amperes passing through a plating 
solution will cause a definite weight of metal to be 



MODERN ELECTRO PLATING. 4 1 

deposited. So, for instance, one ampere will deposit in 
one hour 1.106 grammes of nickel, or 4.05 grammes of 
silver. It is evident, therefore, that by means of an 
accurate ammeter the amount of metal actually deposited 
can easily be determined. 

Tanks. — The plating jars, tanks or vats should be 
of glass, glazed stoneware, enameled iron, or of wood 
lined with asphaltum. The latter are always used where 
the baths are large and in constant use, as they are the 
only ones that are sufficiently strong to withstand hard 
usage, such as is incident to the handling of large pieces 
or a great number of small ones. These tanks should 
be purchased of a dealer in platers' supplies, or from 
tank manufacturers, as it is not advisable to risk the 
loss of solution and the consequent damage to surround- 
ing objects from a poorly seasoned, poorly fitted or 
improperly lined tank. 

New tanks of wood are generally shipped unlined, as, 
if the weather is cold, the asphaltum will be cracked in 
handling the tank, and if the weather be hot the lining 
is likely to be found evenly spread over the bottom of 
the tank to the depth of six inches or more, while there 
is nothing on the sides. Tanks have thus had to be 
relined so often that the custom is now to send the tank 



4 2 



MODERN ELECTRO PLATING. 



and the lining and let the plater line it himself. One of 
the best ways to line a tank is to stretch cheese cloth 
all over the inside, tacking it down neatly on the bottom 
and all four sides; then nail a strip of wood on the upper 
edge of the tank, so that it projects about one-fourth 
inch beyond the inside edges of tank; lay the tank on 







Fig. 14. — Wooden Tank for Platers. 



its side, level it up and heat the lining and pour it in on 
the cheese cloth until it stands even with the strip of 
wood you have just put on; allow this to cool and repeat 
for the other sides, doing the bottom last. The cheese 
cloth strengthens the lining and prevents it from crack- 
ing, just as hair is used to strengthen plaster. Tanks 
lined in this way will stand for years. They should 



MODERN ELECTRO PLATING. 



43 



always be deep enough to leave about six inches between 
the bottom and the largest work. To find the capacity 
of any tank, multiply the length, breadth and thickness 
in inches and divide by 231, as 231 cubic inches make 
one gallon. 

Square or round iron tanks, Fig. 15, are used for 
potash, hot water, etc., and are made in the same shapes 




Fig. 15. 

and sizes as the enameled iron tanks used for plating 
solutions. It is best to buy these of dealers in platers' 
supplies and not from plumbers, as the tanks of the latter 
are frequently very thin and of inferior iron, and are 
liable to break while in use and cause damage amount- 
ing to five or six times the difference in cost. 

The platers who are working in a small way will find 
the best quality of enameled iron cooking utensils serve 



44 MODERN ELECTRO PLATING. 

their purposes very well, but in selecting agate or blue 
enameled basins, pitchers, cups, pails, etc , a very close 
watch should be kept for flaws in the enamel, for if the 
solutions penetrate to the iron they will be destroyed. 
White enamel is usually selected for this reason, as it is 
much easier to discover imperfections in the white 
enamel than in the gray or blue. It also enables the 
workman to see the color of his solution better, which is 
sometimes an advantage. Stoneware crocks and jars 
are also in constant use in plating rooms, to hold the 
various acids, pickles, dips, etc., and the same care 
should also be used in selecting them. 

Heating Xanks* — Small shops usually depend upon 
gas or oil stoves placed under the various tanks or jars 
containing solutions that must be kept hot, such as lye, 
rinsing water, gold solutions, etc., as either offers a means 
of keeping up the desired temperature with very little 
trouble or expense. Larger establishments, however, find 
it cheaper and better in every way to use steam jacketed 
tanks as shown in Fig. 16. These can be purchased in 
regular sizes holding from three gallons up to forty gal- 
lons, and the smaller and medium sizes are rapidly find- 
ing favor in many machine shops and factories where it 
is important to cleanse the work quickly and cheaply. 



MODERN ELECTRO PLATING. 



45 



Still larger tanks for heavy work are made of boiler iron 
and heated by a steam coil placed in the bottom of the 
tank; this usually is allowed to simply lie upon the bot- 
tom of the tank, so that it may be readily removed 




Fig. ib. 

should it become necessary in cleaning the tank or 
repairing the coil. 

In arranging the tanks in the plating room much will 
depend upon the work to be done and the space that is 
available; the only rule that can be given, therefore, is to 
follow the order in which the work is handled in both 
polishing and plating rooms, so that little time and labor 



46 MODERN ELECTRO PLATING. 

will be lost in carrying work back and forth, with the 
consequent dripping of the lye and acids, etc., upon the 
floor. In large establishments it is frequently an impor- 
tant item to have the work thus proceed in a straight line, 
and where it is necessary the tanks for hot water and 
lye, dips, etc., are duplicated to avoid carrying the work 
about. Smaller establishments will, of course, be gov- 
erned largely by circumstances in the arrangement of 
tanks, sawdust boxes, etc. 



CHAPTER IIL 



THE POLISHING ROOM AND TOOLS. 

Polishing should always be done in a separate room, 
in order to keep the plating room clean and thereby pre- 
vent the expense and annoyance caused by dirt and dust 
in the solutions. In large shops this is regarded as a 
matter of course; but many small platers think that a 
separate polishing room is not necessary; that they can 
cover their solutions and get along very well without 
going to the expense of partitioning off a place to do 
their polishing. The consequence is that their shops 
always look as if they had not been cleaned in six 
months; a thick coating of dirt covers the walls, 
benches, countershafts, tools, machines, etc., until it is 
actually a fact that the cleanest place in the shop is the 
floor. This sounds severe, but if the reader will go into 
such a shop and draw his finger along the walls he will 
find it to be a fact. The floor is swept daily and the 
walls are never cleaned. Polishing is a very dirty 

47 



48 MODERN ELECTRO PLATING. 

operation; the lint from the cotton and felt wheels, 
minute particles of leather, emery, oil, tripoli, crocus, 
wax and finely divided metal are continually flying from 
the wheels and work and this dust penetrates every- 
thing. These are the platers that turn out poor work 
and don't see why they can't do as well as their neigh- 
bors. Dirt is fatal to good plating and dirt is insepar- 
able from polishing. 

Buffing and finishing after plating should also be done 
in a separate room for the same reason. Many platers 
have frequent trouble from scratching their work while 
buffing, often making it necessary to replate the article. 
Nine times out of ten such coloring or buffing was 
done in the polishing room where some heavy work had 
been recently done and the coarse emery or scale from 
the work had lodged on the finishing wheels. We are 
speaking now of shops which take rough work and fin- 
ish it. The little shop with a specialty, such as gold and 
silver only, or such other work as replating, etc., where 
heavy cutting down is not done, will hardly go to the 
trouble of duplicating the heads, countershafts, etc., in 
order to separate the work in this manner, preferring to 
take chances on scratching, etc., rather than go to the 
expense and trouble of separating the polishing and fin- 
ishing, but wherever practicable it will pay to do it, and 



MODERN ELECTRO PLATING. 49 

in a manufacturing establishment or large jobbing shop it 
is a necessity. 

Ventilation in a polishing room is of great impor- 
tance to the health of the workmen and should always 
be forced where possible, by a blower exhausting up a 
chimney or into the outer air, with pipes leading from 
the blower to hoods about the various wheels, buffs, etc., 
and these pipes and blower should be large enough to 
maintain a constant current of air about the wheels and 
away from the workmen. Men will do much more 
work in such a room than in one in which they are 
obliged to gasp for breath with wet sponges over their 
nostrils, so that the power thus expended in driving a 
blower has an important result in cheapening the cost 
of running a polishing room. 

The Machinery in this department of plating has 
undergone important changes in the last few years, so 
that more work and greater cleanliness can be obtained 
with the modern machine. The old machines had the 
shafts hung on centers from a clumsy wood or iron 
frame, built in such a way that it was never cleaned, 
because it was too much trouble. The modern machine, 
Fig. 17, has a long shaft running in babbited boxes on 



5o 



MODERN ELECTRO PLATING. 



each side of the driving pulley and the yoke which car- 
ries the shaft is mounted on a stout iron column. This 
arrangement not only gives greater facility in handling 
the work, but also preserves the perfect alignment of 
the boxes and even running of the shaft, which was not 




Fig. 17.— Polishing Head on Column. Fig. 18.— Polishing Head for Heavy Work. 

always the case with the old style of frame, owing to 
the springing of the floors when heavy weights of cast- 
ings are piled near the machines, as is usually the case in 
large shops. The column also offers no obstruction to 
sweeping and shops using them are kept much cleaner. 
Machines for heavy work, Fig. 18, have an upper 
yoke carried on the lower yoke and having boxes 






MODERN ELECTRO PLATING. 



51 



supporting the shaft close to the polishing wheels, thus 
adding greatly to the steadiness and consequent effec- 
tiveness of the machine while allowing the necessary 
room for handling large work below the wheels. 

Work that is too large and heavy to be handled is 

ground and polished by 
means of wheels carried 
on and rotated by a flexible 
shaft, Fig. 19. This is 
nothing more or less than 
the flexible drill of the 
machine shops, which the 
polishers have been quick 
to seize upon and adapt 
to their work, with even 
greater results than this 
tool has achieved in the 
machine shop, as in many 
polishing shops there is 
room for its almost con- 
stant use, which is not the 
case with machinists. It 
is cheaper and quicker than the older swing frame- 
machines and being so much lighter and easier to 
handle, workmen will do much more with it. 




Fig. iQ— Flexible Shaft Grinding. 



52 



MODERN ELECTRO PLATING. 



Small work is polished on bench lathes which consist 
of the same yokes and shafts are shown in Fig. 17 
except that they 
are mounted upon 
benches instead of 
on columns, owing 
to the greater facil- 
ity of handling 
small pieces on a 
bench. 

Very small and 
light work, in shops 
without power, are 
ground and polish- 
ed on foot power 
machines as shown 
in Fig. 20. 

In working pol- 
ishing machines the 
chief points to be 
observed are to use 
soft and flexible 
belts, that will hug the small pulleys closely and not 
jump and jerk when any heavy strain comes upon them 
suddenly and to keep the bearings well babbitted and 




Fig. 20 —Foot Power Polishing Head. 



MODERN ELECTRO PLATING. 53 

free from emery, which would immediately sink into the 
babbit metal and act as a lap, cutting out the shaft very 
rapidly. 

Bearings not provided with closed oil cups should 
have covers of tin or brass over the oil holes and 
the foreman should see that the covers are kept in 
place. If there is room for it in the cups, a little 
cotton waste laid in them and changed as fast as it 
gets dirty will do a good deal towards keeping 
emery out of the bearings of all machinery in the 
polishing room. 

Where possible the machines should be arranged so 
that the workmen stand facing the light, as this permits 
them to see what they are doing without stopping and 
turning their work about, thus enabling them to do more 
work in a given time than they could if the light came 
from another direction. This may seem a trivial matter, 
but any polisher will assure you that it is not, and in a 
business where the chief expenditure is for labor, every 
saving of time is important, especially where a large 
number of men are employed. 

Glass or metal shades should be placed over each 
wheel to protect the eyes of the workmen; sometimes 
this is obviated by extending the hoods far enough over 
the wheels to serve as a shield. When this is done the 



54 



MODERN ELECTRO PLATING. 



hood is made so that it may be readily slipped back 
upon the blower pipe when changing wheels, etc. 

Rattling or Tumbling Boxes. Small objects, such 
as small castings, stampings, etc , that are not required to 
have square edges, are best cleaned by tumbling, or 
rattling, as it is called in foundries. Large quantities of 
work are thus easily and cheaply cleaned without much 
manual labor, which is the expensive item in polishing. 
If rough castings are being worked, the sand, scale, 
etc., adhering to them is allowed to remain in the barrel, 
where it acts as a polishing powder, brightening the 
parts which are not reached by the metal of other cast- 
ings; but when tumbling for a bright finish, the sand, dirt, 
etc., are exhausted by means of the blower, so that the 
surfaces are finely polished by friction only — burnished, 
as it were, by rubbing against other metal of the same 
kind. A strong exhaust should be kept up when polish- 
ing in this way, or the finish will be dead instead of 
bright. It is a principle in burnishing that you cannot 
get the burnished surface smoother than the burnisher, 
so that a little consideration will show that bright work 
is only obtained by long-continued tumbling, and the 
bright finish comes rather quickly after all the pieces 
in the barrel have become smooth. It is, therefore, 



MODERN ELECTRO PLATING. 



55 



necessary to handle the work in batches, and not to 
add more work after the batch has been some time in 
the barrel, or the work will not finish evenly, and time 




Fig. 2i .— Egg-Shaped Tumbling Box. 



will be lost instead of gained. The speed should be 
regulated so that the articles may have time to slip 
down upon and slide over each other as much as 
possible. If .the barrel turns too fast they will hug 



56 MODERN ELECTRO PLATING. 

the sides of the barrel and be carried around with it; 
about 40 to 60 revolutions per minute is correct; if too 
slow, the action is unnecessarily prolonged. Fig. 21 
shows a new form of tumbling barrel far superior to 
anything else within our knowledge. The barrel is egg- 
shaped; it has a section of exhaust pipe connected 
to the hollow journal at one end and a tight and loose 
pulley at the other end. No gearing whatever is used. 
Three special advantages are found in the egg-shape: 

It gives the contents a double motion or action — 
from ends to center and from sides to center — caus- 
ing a thorough mixing and rubbing together of all the 
parts contained therein, cleaning and polishing the con- 
tents better and quicker than any other form of barrel. 

It requires less power, as the end motion causes the 
contents at the ends to tumble into the center because 
of assuming the perpendicular earlier than those parts 
at the side. 

It runs with less noise, because the contents are kept 
moving in two directions at the same time, doing away 
entirely with the intermittent motion so noticeable in 
other forms; doing away with gearing also lessens the 
noise. 

It is lined with a sectional lining of hard iron, which 
can be cheaply and quickly replaced when worn out, 



MODERN ELECTRO PLATING. 57 

making the barrel as good as new. A current of air is 
forced through the barrel by an exhaust fan, which 
removes the dust and carries it out through pipes 
arranged for the purpose, and the room is kept perfectly 
free from this nuisance. The workmen are thus enabled 
to do their work comfortably. It is said to do more and 
better work, takes up less room and requires fewer 
barrels for a given amount of work than any other. 
Small sizes of the barrel, for finishing small work ready 
for plating without hand labor, are now being made. 

Emery or Corundum Wheels are used for grinding 
off the lips of castings, imperfections caused by breaks 
in the moulds, etc. These wheels are of varying thick- 
nesses, grades, sizes and shapes and should be run 
at correspondingly varied speeds in order to get the 
best work out of them. The same grades of wheel 
from different makers sometimes vary slightly in speed 
and these details had therefore best be obtained from 
the manufacturers. If run too fast they will glaze and 
require dressing to keep them sharp. Too much 
pressure when grinding will also glaze a wheel. The 
grinder should understand dressing wheels, as it is 
often necessary in balancing them, as well as in keep- 
ing the surface true and sharp. 



58 MODERN ELECTRO PLATING. 

Flat wheels are dressed with an emery wheel dresser, a 
tool generally listed by dealers and therefore unneces- 
sary to describe here. Curved surfaces, moldings, 
ogees and angles are ground with wheels specially turned 
up by the workman to fit the surface, in order to do the 
work quickly while preserving the shape; as in pre- 
paring stove work for nickeling, etc. This turning is 
best accomplished by using a diamond turning tool, 
which can also be found in the market. Such wheels 
when glazed are also dressed with the diamond tool. 
Work having hollows too small for the large wheel is 
ground with a large and small wheel on the same arbor. 
This holds true in polishing as well. 

Canvas Wheels are next used on all large surfaces. 
These are made of coarse duck or canvas, cut into discs 
of the required size and glued or cemented together 
under pressure, after which they are bored out to receive 
the arbor, put on the machine and turned up to the 
required shape with a wood turner's tools. Some shops 
make their own canvas wheels, but it is generally 
cheaper to buy them. Both glued and cemented wheels 
have their advocates. The former claim that there is 
little difference between them and glued wheels are 
cheaper; the latter declare that a glued wheel is too 



MODERN ELECTRO PLATING. 



59 



hard and will not polish uneven surfaces as well as a 
wheel well made with a flexible rubber cement, and that 
a slight increase of cost is more than made up by speed 
in polishing. It is a matter which every polisher will 
decide for himself, according to the nature of his work. 
Canvas wheels are set up like wooden wheels. The 
grade of emery will depend upon the nature of the work 
to be done. If very rough and coarse iron surfaces are 
to be worked, No. 70 emery is first used, followed by 
No. 90; if the surface is fairly smooth, No. 90 is used at 
first followed by No. 120. If the metal is brass tripoli 
is used for cutting down. 



Wood Polishing Wheels, Fig. 22, are made of thin 
sections of pine, glued together with 
the grain crossed, bored and turned 
up as previously described, and 
finally, if flat, covered with best oak 
tanned leather, glued on the rim 
and turned up true, if it needs it. 
These wheels are set up by covering 
the leather with hot glue and then 
rolling in powdered emery of the 
desired grade. Right here is a 
source of frequent trouble. It often " ^ 




6o 



MODERN ELECTRO PEATING. 



happens that in gluing up a lot of wheels of different 
grades the loose particles of emery on the 70 wheel 
will get into the glue brush and be deposited on a 90 
or 120 wheel. Nobody sees it, of course, until the 
polisher finds that he cannot get the scratches out of his 
work until he changes wheels. Much time is often lost 
in this way. The remedy is to have separate glue pots 
and brushes for the various grades. When the emery 
is no longer sharp it is soaked off the wheel and fresh 
powder again glued on. It is customary to glue and set 
up wheels the last thing before quitting work at night, 
in order that the glue may have all night to dry and 
thus get thoroughly hardened, so as to give the best 
service. Only the very best glue will stand the work. 



Polishing Wheel Cleaner ♦ Users of leather covered 

emery wheels 
should use a 
cleaner. By 
placing the worn 
wheel in this 
machine and let- 
ting it run a few 

Fig. 23.—Folishing Wheel Cleaner. . . , , 

minutes with the 
water just touching the rollers, all of the glue and 




MODERN ELECTRO PLATING. 6 1 

ornery will be removed without damaging or loosen- 
ing the leather covering. This machine, Fig. 23, has 
two rows of movable rods (only one shown in cut), 
to keep the wheels from falling over. The idle 
roller also has two positions for different diameters of 
wheels. As it requires no attention or time to use it, 
the cost of this machine will be saved in a few 
weeks' labor. Speed should be about 20 revolutions. 
The other wheels, which would be injured by water, 
are cleaned with buff sticks which are made by glueing 
a stick and dipping in No. 15 to No. 36 emery. 

Leather Wheels are used in polishing and fine grind- 
ing, where a flexible wheel is necessary. There are 
many different kinds, which may be classed under this 
head, and while every polisher has his preferences, 
if he has not the kind he prefers, he can use another. 

Walrus Wheels are made from the thick, specially 
tanned hide of the Walrus, and are unequaled for work 
requiring the wheel to be turned up to a thin, moulded 
edge or curve, as they are thick enough to allow such 
shapes to be made from a single piece, while the thinner 
discs of other leathers are apt to leave ridges of glue 
where it will mark the work unless greater care is taken. 



62 MODERN ELECTRO PLATING. 

Bull Neck Wheels are made, as the name indicates, 
from the thickest and toughest portions of hides, and 
form" a harder wheel than Walrus. They are much 
used in stove, bicycle and other steel and iron work, and 
are turned and glued up as previously described. The 
other leather wheels are similar in their nature, differing 
only in the mechanical structure and degree of hardness, 
the desirable quality being the ability to hold the 
emery up to the work without allowing any lumps or 
unevenness in the glued emery to cut into or gouge the 
work; this becomes more and more important as 
the finishing proceeds, or softer metals than iron are 
being worked, and so still softer wheels are used, made 
from felt. 

Felt Wheels are used with emery and glue, or with 
polishing compositions. They are of varying degrees 
of hardness and either white or gray. Certain peculi- 
arities of felt wheels, though well known to professional 
polishers, have never, to our knowledge, been printed, 
and it may be serviceable to mention them here. The 
first point is that the higher priced wheels are the cheap- 
est, the extra price being more than made up in the 
increased durability and uniformity of the white wheels, 
which wear much longer, balance better, and give a 



MODERN ELECTRO PLATING. 63 

superior finish, than do the cheaper gray felt. The 
second point lies in the fact that the wool in a felt wheel 
will catch fire under too hard pressure, and once ignited 
it will smoulder away under the emery and glue until it 
has burnt a long hole in two directions through the felt, 
without showing any signs until the coating breaks in 
from the surface, and the wheel, being then out of bal- 
ance, begins to pound. The only thing to do, in such a 
case, is for the workman to turn the wheel down to 
where the felt is solid and start over again. Burning is 
always the result of carelessness, and it is amusing to 
hear a workman claim that the hole was there when he 
got the wheel, forgetting that in such a case the^wheel 
would be out of balance and he could not have run it 
that way without balancing the wheel. 

Cotton Buffs, Figs. 24, 25 and 26, are made of discs 

of muslin and are used with pastes 

of tripoli, crocus or rouge, for fin- ^^~— ^ 

ishing or coloring. They vary in '"^- >y "^ 

softness according to the nature of - f / ^ ^ N % 

g I I / rs \ \ } :: 
the work, their material and the I . V // / 

method of manufacture. The hard- \ \^ — y y ^ 

est buffs are made in sections from -_>^-~ ;: " 

duck, stitched or quilted together, Fig. ^.-Medium Buff. 



64 



MODERN ELECTRO PLATING. 



while the soft buffs are of muslin stitched only at the 
center. As many sections as may be necessary to 
make the desired thickness of wheel are put on the 
arbor and the flanges set up until the wheel runs prop- 
erly. Too tight flanges will cause the buff to spread 







Fig. 25. — Hard Buff. 



Fig. 26 — Soft Buff. 



and run unevenly; if too loose, the wheel will slip, 
making bad work. 



Grease Wheels* When a leather covered wood, 
leather or felt wheel has had the emery on it worn 
down smooth by use, so that it no longer cuts freely, a 
little tallow or oil is applied to its face, a little 180 emery 
cake or polishing paste is applied and the work gone 
over again. The wheel thus prepared is called a grease 



MODERN ELECTRO PLATING. 6$ 

wheel. Grease wheels are made only from wheels 
set up from 120 or finer emery. The work is then 
gone over again, without oil or tallow on the wheel, 
and this use of a worn grease wheel is known as 
"dry fining." After the grease wheel is worn down 
perfectly smooth, a little pumice or polishing paste is 
applied, a flint stone is held against the face to glaze 
it over and at the same time remove any particles 
of sharp emery that may still be there and the work 
is gone over a fourth time. This is known as color- 
ing and produces the highest finish on steel, leaving 
the work lustrous and beautiful in appearance. This 
final polish has a great influence upon the appearance 
of the plating and practical men can tell at a glance 
in looking at plated steel, whether the polishing was 
a "three wheel" or "four wheel" operation. 

In such cases it is customary, when doing small work, 
to place the fining and coloring wheels side by side 
on the same arbor, separated by collars, so that the 
successive operations may be done with one handling. 

Belt Straps are made of canvas or duck, from one 
to two inches wide, glued and set up with emery 
as previously described, and used in polishing flat 
surfaces, such as cutlery, flat springs, large tubes for 



66 MODERN ELECTRO PLATING. 

bicycle frames, etc. They are run on flanged pulleys, 
one of which is supported on a standard and the other, 
which is the driver, is mounted in place of a wheel on 
one of the polishing heads. 

Balancing Wheels* All wheels running as fast as 
they must in polishing require to be very carefully 
balanced or they will "pound" or "chatter," making 
good work impossible. Balancing is accomplished 
by placing the wheel on an arbor and rolling it on 
two level, knife edged strips of metal, one on each 
side of the wheel. Thus suspended the wheel will 
stop with its heaviest part downward, and with a 
little chalk to mark the wheel and some small pieces 
of sheet lead to fasten on the side of the wheel, 
balancing is quickly and easily performed. It may 
also be done by hanging the arbor between spur 
centers, as pulleys are balanced in a machine shop, 
but the rolling method of balancing on bars, which 
is precisely the method the watchmaker employs in 
poising a watch balance, is the quickest and best. 
Balancing should not be done until the wheel has 
been turned true on its arbor and glued up. It 
should never be omitted. A properly balanced wheel 
will run true, even and noiseless at any speed. 



MODERN ELECTRO PLATING. 



6^ 



Speed of Wheels. Wheels and buffs are run from 
2,000 to 2,500 revolutions per minute, depending on 
their size and the nature of the work; and here we 
would like to make a suggestion, 
which will materially increase the 
output of any polishing shop. If 
we examine the table of emery 
wheel speeds given herewith, we 
shall find that the speed increases 
rapidly as the wheel gets smaller. 
Most people imagine that this table 
is merely a guide to the safe run- 
ning speed of the wheel and that 
it is given in order that the wheel 
may not burst while running. This 
is an error; the table simply means 
that the given number of revolu- 
tions for any size of wheel is that 
which will drive the circumference 
or cutting surface of the wheel at 
its proper cutting speed to enable 
the wheel to do the best work and 
the most of it. Machinists understand the point 
thoroughly, and their shops are filled with cone-pul- 
leys to enable them to keep up the cutting speed 





Revol 


jtions 


Diame- 


Per Minute. 








Inches. 


Mini- 


Maxi- 




mum. 


mum. 


I 


l8,0OO 


l8,000 


I# 


1 0,000 


14,006 


2 


7,900 


11,000 


2^ 


6,330 


8,800 


3 


5.275 


7,400 


VA 


4,500 


6,300 


4 


3,950 


5,500 


\Vz 


3,500 


4,900 


5 


3,160 


4,400 


6 


2,640 


3,700 


7 


2,26o 


3,l60 


8 


1,980 


2,770 


9 


1,760 


2,460 


10 


1,580 


2,210 


12 


1,320 


1,850 


H 


1,130 


1,580 


16 


990 


1,380 


18 


^80 


1,230 


20 


790 


1,100 


22 


720 


1,000 


24 


660 


920 


26 


600 


850 


30 


500 


735 


36 


400 




42 


350 




48 


300 





68 MODERN ELECTRO PLATING. 

on work of varying sizes. In the polishing depart- 
ment this is neglected. The pulleys and counter- 
shafts are arranged to run the largest wheels properly, 
and when they are turned down from time to time, 
the work simply proceeds more and more slowly 
until the wheel is worn out and a new or larger one 
substituted. Now, it is useless to tell a polisher to keep 
up the cutting speed of his wheels, unless you give him 
the means of doing so. There should be four-step or 
five-step cone pulleys on the line shaft for each machine, 
belted to the other cone of the pair, on a jack shaft 
which also carries the driving pulley leading to the 
wheel arbor of the machine. This would enable pol- 
ishers to speed up as their wheels got smaller, and the 
increased output of the shop would repay the outlay 
several times over, each year. The cones could be 
made of wood, and would add nothing to the weight and 
consequent wear on the line shaft. Now that so many 
large shops are being fitted up regardless of expense in 
order to get a great output of work, this is a point that 
should not be neglected. 



Direction of Polishing* In all polishing operations 
the successive grindings should constantly cross one 
another as far as possible, otherwise the scratches will 



MODERN ELECTRO PLATING. 69 

not be taken out, and the work will not have an even, 
mirror-like polish. The wheels should turn so that the 
lower edge moves away from the workman and the 
work is held up to the wheel on its under side, so that the 
dirt, grit, etc., will fly back into the hoods, while the 
work, in case of accident, would drop away from the 
wheel instead of falling on it, as would be the case if 
another position were chosen for the work. The pres- 
sure should be light and even and the grinding should, 
in each case, be continued as long as any of the 
scratches made by the coarser previous operation 
remain on the work; when only the marks of the wheel 
in use can be seen, the work may be considered ready 
for the next operation. 

Polishing Materials* In order to hold fine powders 
on the wheels and buffs they must be mixed with some 
medium that will perform this office, and at the same 
time act as a lubricant to the work. It was formerly 
customary for polishers to buy their powders and mix 
them with varying proportions of oil, tallow and bees- 
wax, which was then cast into blocks. The objections 
to this were lack of uniformity and the use of too much 
oil, wax, tallow (or all three) in proportion to the 
amount of powder, which had a tendency to " stuff" 



7<D MODERN ELECTRO PLATING. 

(or fill up) the buffs so much as to interfere with their 
working properly. The manufacturers of polishing 
powders have taken up the question, and succeeded in 
turning out cakes that combine all the necessary quali- 
ties of such a composition — namely, the largest propor- 
tion of powder with the least amount of binder, and a 
cake that is hard enough so that a small amount of com- 
position may be evenly distributed over the entire cut- 
ting surface of the buff by holding the cake against the 
buff while it is in motion, and the paste so it will cling 
to the buff, leaving the metal clean. The manufactured 
cakes also have their keeping qualities greatly improved 
from the absence of soft greases, which were liable to 
turn rancid, and thus injure the working qualities of the 
cake. These polishes are generally designated by the 
manufacturer in such a way as to show the metal they 
are intended to be used upon, and the grade of the pol- 
ishing material as: Nickel Rouge, Hard No. i; 
Nickel Rouge, Hard No. 2; Nickel Rouge, Soft; Silver 
Rouge, Hard; Silver Rouge, Soft, etc. When order- 
ing these polishing materials the purpose for which they 
are to be used should always be stated, as the order can 
then be filled with that variety which is best adapted to 
the work in hand; and cleaner, quicker and better work 
will thus be produced with less waste of material. 



MODERN ELECTRO PLATING. 7 1 

Tripoli is used in three grades — coarse, for cutting 
down rough or hard brass, etc., on hard buffs; medium, 
used on medium buffs for smoothing, cutting down 
softer metals, etc.; fine, on soft buffs, for coloring only on 
cheap work, and for use in place of the harder rouges 
where the color of the latter is objectionable, and it is 
difficult to get it out of the work. The various manu- 
facturers have special names for their different grades, 
but it will be sufficient when ordering to state the kind 
of work and buff you intend to use the cake upon. 

Crocus is an oxide of iron, made by calcining sul- 
phate of iron in great heat and then grading it into pol- 
ishing powders. The more calcined part is of a bluish 
purple color, coarser and harder than those portions 
which have had less heat, and is called crocus, while the 
softer and redder portions of the charge are called 
rouge. Crocus compositions of various grades are 
largely used for coloring iron and steel. 

Rouge is softer than crocus, and is used for coloring 
brass, gold, silver and the softer metals. It is divided 
into numerous grades, which are distinguished by the 
names of the metals for which they are especially 
adapted, as: silver rouge, gold rouge, etc. Its red color 



72 MODERN ELECTRO PLATING. 

makes it particularly adapted for brass, gold, and some 
other metals where the reddish tinge sets off the color 
of the metal on which it is used. The finest, or gold 
rouge, should be used on canton flannel buffs. 

Vienna Lime is a pure anhydrous lime, obtained 
from Vienna, and is extensively used where the red 
color of rouge is objectionable. It must be used while 
slacking or it is of no value, so the custom has been to 
mix it with oil, wax, etc., in small batches, and keep the 
supply in the air tight tin or bottle in which it is received 
from the dealer. Even then, great waste has attended 
its use on account of air slacking. Lately, however, 
several manufacturers have succeeded in making suit- 
able compositions of Vienna lime and pressing them into 
cakes, which are dipped in melted parafine and wrapped 
in parafined paper. Thus prepared, the lime holds its 
polishing properties for several months, and these cakes, 
under various names, are meeting with considerable 
favor for buffing nickel, silver and other metals which it 
is desirable to keep white. 

Brushes, After the work is colored it is necessary 
to wash off the oil, grease and polishing material which 
still remains on it. This is done with brushes. The 



MODERN ELECTRO PLATING. 73 

brushes for large work are made of tampico, mounted 
on polishing heads and kept wet with water. Small 
work is cleaned with bristle brushes, which are carefully 
selected so as not to injure the polish on soft metal. 

The work is then dipped in hot caustic potash, then in 
hot water, scoured well, rinsed and hung in the bath. 

Pumice Stone is used in powder for scouring the 
work, to remove all traces of oil, grease, lye, etc., just 
before hanging the work in the plating solution; also in 
lumps, for scouring spots that refuse to take the plating, 
which is a common fault in replating old trays, baskets, 
etc., that have been badly corroded. 

It is customary to have a large sink, lined with lead, 
deep enough to receive all drips and rinsing water, and 
to hold the rinsing water, pans, brushes, pumice stone, 
etc., and to do the scouring on boards placed over or in 
the sinks, so as to catch all waste, rinsing water, dirt 
from the buffs and polishing powder which is washed 
from the work. In large establishments, where much 
silver and gold work is done, this sink is placed on top 
of a deep waste tank into which the sink discharges all 
waste water; the waste tank discharges from a pipe 
near the top at the end opposite to that from which the 
discharge enters from the sink, so that the dirt, which is 



74 MODERN ELECTRO PLATING. 

rich in metal, may have time to sink to the bottom 
before the water finds its way out of the tank. This 
tank is cleaned occasionally, and the dirt taken from it 
is dried and sent to the refiner. This dirt varies greatly 
in value (from $20 to $120 per barrel) according to the 
nature of the work done in the shop. .Shops using the 
cheaper metals, however, rarely save their wastes in 
this way, as they are not worth enough. 

Scratch "Brushes are of two kinds, — large, heavy 

brushes, with coarse wire, used exclusively for cleaning 

castings, and smaller brushes of finer wire, used in the 

plating room to burnish down the layer of deposited 

metal when for any reason it is not taking well, or when 

an extremely thin and adherent coating is desired. The 

speed of scratch brushes is an important factor in their 

life and usefulness. The very best and softest brushes 

will crystallize and break off at the hub if the brush is 

run too fast. The subjoined table gives the proper 

speed for the various size of wires. 

Wire .002 of an inch should run 1,500 revolutions per minute. 
Wire .003 of an inch should run 1.200 revolutions per minute. 
Wire .004 -of an inch should run 1,000 revolutions per minute. 
Wire .005 of an inch should run 8co revolutions per minute. 
Wire .006 of an inch should run 600 revolutions per minute. 
Wire .008 of an inch should run 500 revolutions per minute. 



MODERN ELECTRO PLATING. 75 

In using wire larger than .005-inch it is best to use 
swing brushes. These consist of an iron or wooden 
hub, which can be readily taken apart and new wires 
substituted. It is the only brush that will stand with 
heavy wire. A smaller size of swing brush, for mat- 
ting or frosting finished work, is also much used. 

In working the brush do not bear too hard against the 
wire. The work should be just brought in contact with 
the ends of the wires. If too much pressure is used you 
bend the wires and do not get as good results. After 
using the scratch brush awhile the wires will become 
tangled and the wheel will scour or burnish instead of 
cutting or matting the surface. When this is the case, 
simply turn the wheel the other side out on the polishing 
head, so that the wheel will run the other way and 
the wires will cut rapidly, finally straightening them- 
selves out, and then tangle up the other way. In using 
soft, fine brushes in the plating room, when it is desired 
to matt the work, hold an old file against the brush a 
moment, and the ends of the wires will become bent so 
that they cut the work instead of burnishing. Scratch 
brushing in the plating room is always performed with a 
stream of water containing a little soap, soap root 
licorice, beer or other frothy liquid trickling down upon 
the brush so as to keep brush and work constantly wet. 



CHAPTER IV. 



PREPARATION OF WORK FOR PLATING* 

Much of the success or failure of plating may be traced 
directly to the degree of skill and care used in preparing 
the work before it is placed in the solution. It is not too 
much to say that nine-tenths of the blistering, stripping, 
turning yellow, and other troubles which only show after 
the work is done, may be traced to its improper pre- 
paration. 

Iron and Steel castings, forgings, etc., are first 
pickled and scratch brushed or " rattled" to remove the 
scale if necessary, then cut down with 70 emery on a 
canvas wheel; then with 90 emery until all marks of 
the 70 emery are taken out; they are then "fined" on 
a 120 wheel, then "greased" with 150 emery on a 
grease wheel. This is followed by " dry fining " on a 
well worn grease wheel and then colored on a wheel 
glazed with pumice and a flint stone, as previously 



MODERN ELECTRO PLATING. 77 

described. This gives the finest finish and the most 
durable plating, if the workman has been careful in 
each operation to get out all marks of the previous or 
coarser grinding. In many cases on cheap work,' the 
dry fining is omitted and the omission can be generally 
detected after the plating is done. Smoother work, 
such as replating, or work that has been turned up in a 
lathe, or otherwise machined, has one or more of the 
first grindings omitted, according to the circumstances 
and the degree of smoothness when the articles come 
into the polisher's hands. 

Tableware, a knife, for example, is roughed out with 
90 emery on a felt wheel, then with 120 emery, and 
then with 150 emery on a grease wheel, until all marks 
of the 120 emery are polished out. It is then dry fined 
and colored. The finishing wheels should be kept as 
smooth as possible in order to do the best work, as the 
plating will wear much longer if the steel be made per- 
fectly smooth. After the knife is colored, it is boiled in 
hot potash water to remove all grease that is on the 
work. It is then scoured with powdered pumice stone 
and water, using a stiff bristle brush, until clean water 
will run off and show no traces of grease on the knife. 
A fine copper wire is then twisted on to the handle and 
the work dipped into a pickle of one gallon of muriatic 



78 MODERN ELECTRO PLATING. 

acid and one gallon of nitric acid with one quart of 
water and a handful of salt, rinsed and hung in the solu- 
tion. The same general procedure is followed on all 
first-class steel and iron work. 

Brass and Copper, if already smooth, can be pol- 
ished with tripoli on a cotton buff. If rough, they may 
be roughed out with 120 emery, or coarse tripoli, then 
put on the grease wheel and then polished with rouge 
and finally with Vienna lime on a soft buff. They are 
then dipped in potash, rinsed, and then in a cyanide 
dip — two or three ounces to a gallon of water — rinsed in 
clean, cold water, brushed with powdered pumice stone, 
as before described, rinsed and hung in the solution. 

Zinc is roughed with fine emery and polished with 
Vienna lime and oil. Britannia metal or lead must not 
be left in the potash too long, or it is liable to eat out 
the lead and tin; the best way is to brush the work 
thoroughly with the potash water instead of dipping it; 
then scour with pumice stone. 

Lead, Tin and Brittania are polished on a walrus 
wheel with pumice stone. The pumice is mixed with a 
little oil to make it hold together. A little of this is 



MODERN ELECTRO PLATING. 79 

then placed on the work and it is held lightly against 
the wheel. Do not press hard on the work, or it will 
cut holes in the metal instead of polishing. After pol- 
ishing it is then scoured with pumice as before, to 
remove all oil, and rinsed, then plated. Large silver 
trays are polished by hand with lump pumice stone 
and water. After all the fine holes are taken out in 
this way, a Scotch stone and water are used until all 
marks of the pumice are removed. It is then buffed 
with a seahorse wheel and pumice (as described for 
lead), then with hard rouge, and finally colored with 
soft rouge and alcohol. In this way a large flat surface 
can be made very smooth. 

When the operations described above have been thor- 
oughly carried out, the work will generally take a very 
firm and adhesive coat of metal if ordinary care is taken 
in plating with copper, brass, silver or gold, but nickel 
may give some trouble if deposited directly upon the 
object, especially if it be steel. 



CHAPTER V. 



THE ACTION OF DIPS AND PICKLES. 

While the best polish is secured by grinding and 
polishing on a wheel, many articles will not admit of 
this, either from their nature or form, or because it 
would be too expensive to treat them in this manner. 
Such articles are therefore cleaned chemically by 
immersing them in solutions which dissolve the scale, 
grease, etc., adhering to them, and leave a clean but 
more or less rough surface which has to be smoothed 
afterwards. Those solutions which are intended for 
prolonged action on rough work are called pickles and 
those which are intended for an instantaneous action on 
a surface already smooth are called dips. There is 
little difference between their action, except that the dips 
are intended to secure uniform action on the surface of 
the work, which is accomplished by using strong acids 
with little or no water, while pickles usually contain a 
large proportion of water and depend upon continued 



MODERN ELECTRO PLATING. 8 1 

action, often accompanied with vigorous brushing to 
throw off the scale. 

Generally speaking, success in using the various pick- 
les and dips depends chiefly upon quick and careful 
handling, rather than upon the dips themselves, the 
main points in using the latter being to secure perfect 
cleanliness of the work (without which uniform action 
is impossible), and to see that little or no water is 
-carried into the dip. This is secured by dipping the 
work in boiling lye and then rinsing in boiling water, 
shaking a moment to drive off the water and then 
immersing in the dip. Large numbers of small 
articles, strung on copper wire, may be handled in 
this way with great speed, the heat drying them 
almost immediately. If the work comes from the dip 
smooth, but of uneven color, you can make up your 
mind the work is not clean; if the color is even or 
nearly so, but is pitted or roughened in places, the 
trouble is water in your dip. In using bright dips, 
and also in using oxidizing dips while finishing work, 
the time the work remains in the solution has an 
important influence upon the result; in many cases a 
number of colors or surfaces may be produced by 
one dip, simply by altering the time the work is 
allowed to remain in the dip. 



82 MODERN ELECTRO PLATING. 

Black Pickle for Iron is made by mixing in a stone 
jar or tank, according to quantity 

Sulphuric acid 66° B I part. 

Water 15 parts. 

Hydrochloric acid may be substituted for the sul- 
phuric if desired. This is used chiefly for removing 
scale from castings and forgings. 

Bright Pickle for Iron* A pickle which leaves the 
metal bright is made by mixing slowly in the order 
named: 

Water 10 quarts. 

Concentrated sulphuric acid 28 ozs. 

Zinc 2 ozs. 

Nitric acid 12 ozs. 

Pickle for Copper, Brass, Etc* Forgings, punchings, 
etc., are pickled in dilute sulphuric acid to remove scale, 
and then cleaned and brightened by dipping in a solu- 
tion made up as follows: 

Sulphuric acid 66° B 50 parts by weight. 

Nitric acid 36 B 100 parts by weight. 

Common salt 1 part by weight. 

Lamp black 1 part by weight. 

After dipping and rinsing in hot water the work is 
ready for polishing and coloring. 



MODERN ELECTRO PLATING. 83 

Bright Dip for Copper or Brass* Copper or Brass 
work that is not to be buffed or polished is best dipped in 
first a pickle of 

Nitric acid 36 B 200 parts by weight. 

Common salt 1 part by weight. 

Lamp black 2 parts by weight. 

After pickling until clean, they are thoroughly rinsed 
in boiling water, allowed to dry a moment and plunged 
into a " bright dip" of 

Nitric acid 40 B 75 parts by weight. 

Sulphuric acid 66° B 100 parts by weight. 

Common salt 1 part by weight. 

Cyanide Dip for Brass* Potassium cyanide in ten 
times its weight of water is used as a preliminary dip 
when plating articles that would have the polish injured 
by the acid dips. The work must be allowed to remain 
longer in this than in the acids. 

Pickle for German Silver. German silver may be 
cleaned in the bright dip for brass, or in a preliminary 
pickle of dilute nitric acid and water (12 to 1), fol- 
lowed by a dip of equal parts of sulphuric and nitric 
acids, and then by rinsing in boiling water and drying in 
sawdust. Use sawdust that contains no tannin. 



84 MODERN ELECTRO PEATING. 

Pickles for Gold Alloys, While properly belonging 
to the goldsmiths' art, it may occasionally be useful to 
the plater to know how such pickling is done, as it often 
saves much time in coloring new work. 

The methods given are distinctly inferior to "running 
off the green," as detailed in the chapter on stripping, 
but may occasionally prove useful on some kinds of 
work, or in saving time where it is desired to remove as 
much as possible of the coating before putting in the 
bath for removing the green. 

Gold alloys, especially those containing copper, assume 
an unsightly, dark brown exterior, owing to the copper 
oxide generated by the repeated glow-heating during 
work. In order to remove this, the object must be 
pickled, and either highly diluted sulphuric or nitric 
acid is used, according to the color desired. 

If w r orking with an alloy consisting only of gold and 
copper, either sulphuric or nitric acid may be used 
indefinitely, since gold is not attacked by either of these 
acids, while copper oxide is easily decomposed thereby, 
and after having been pickled, the article will assume 
the color of pure gold, because its surface is covered 
with a layer of the pure metal. 

If the alloy is composed of pure gold and silver, how- 
ever, only nitric acid can be employed, and the article is 



MODERN ELECTRO PLATING. 85 

left immersed in it only for a short time; this acid dis- 
solves a very small portion of the silver, and the article 
also assumes the color of pure gold. 

When working with an alloy which, besides the 
gold, contains both copper and silver, the process of 
pickling may be varied in accordance with the color 
desired to be given to the article. If the pickling is 
performed in sulphuric acid, the copper alone is dis- 
solved, the article assuming a color corresponding to a 
gold-silver alloy, which now constitutes the surface of 
the article. 

If nitric acid is used, it will dissolve the silver as well 
as copper, and in this case a pure gold color is pro- 
duced. 

Pickling is done by first feebly glow-heating the 
article and cooling it; this operation is for the purpose 
of destroying any fat from the hands or other contam- 
ination adhering to the article. If it was soldered with 
some easily flowing solder, this glow-heating must be 
omitted, but it may be cleansed from impurities by 
immersing it at first into very strong caustic lye, and 
rinsing it with water; it is then laid into the acid. 

The acids are employed in a dilute state, taking 40 
parts water to 1 part concentrated sulphuric or nitric 
acid. If more articles than one, they had best be laid 



86 MODERN ELECTRO PLATING. 

beside each other in a porcelain or stoneware dish, the 
diluted acid is poured over them, and some article is 
lifted out from time to time to watch the course of pro- 
ceedings, whether it has assumed a yellow color. 

When to satisfaction, they are rinsed with clean water 
and dried. While pickling for the purpose only of 
causing the color peculiar to gold to appear, the process 
of coloring has for its object to lend the appearance of 
very fine gold to an article of an indifferent alloy. 
Various mixtures may be employed for the purpose, 
and we give two recipes below which are very appro- 
priate : 

Mix 2 parts saltpeter, i part table salt and 6 parts 
alum with 6% parts water, and place in a porcelain dish 
for heating. As soon as you notice that the mixture 
begins to rise, add i part of muriatic acid, raise the 
whole to boiling and stir with a glass rod. 

The article to be colored, and previously treated with 
sulphuric acid, as specified, is suspended to a hook 
either of sufficiently thick platinum wire or glass; it is 
then introduced into the rather slow boiling bath, and 
moved around in it. It is to be taken out in about three 
minutes, and rinsed in clean water, inspecting its color 
at the same time. If not to satisfaction, it is returned 
to the bath, and this withdrawing or reintroducing is 



MODERN ELECTRO PLATING. 87 

repeated until the desired color is obtained. By the 
latter immersions the article is left only one minute at a 
time in the fluid. 

When sufficiently colored, the article after rinsing, 
will be of a high yellow and mat color; it is washed 
repeatedly in water to remove the last traces of the 
bath, and then dried in hot sawdust. 

In place of drying in sawdust the article may also be 
dipped in boiling water, leaving it in for a few seconds; 
the adhering water will evaporate almost instantan- 
eously when the article is withdrawn. 

The second coloring method consists in pouring 
water over a mixture of 115 parts table salt and 230 
nitric acid, so that the salt is dissolved; it is then to be 
heated until a dry salt residue is again present. This 
residue is mixed with 172 parts fuming muriatic acid 
and heated to boiling, for which purpose a porcelain 
vessel is to be used. 

As soon as the pungent odor of chlorine gas begins 
to evolve, the article to be colored is immersed, and left 
for about eight minutes in the fluid for the first time; in 
other respects a similar treatment, as specified above, is 
also used for this method; if the article colored was pol- 
ished previously, a subsequent polishing is unnecessary. 
On account of the vapors evolved by the coloring 



88 MODERN ELECTRO PLATING. 

baths, which are dangerous to health, the operations 
should be performed either under a well-drawing flue, 
or what is still better, in open air. 

Always keep the various pickles, dips, etc., for the 
various metals separate from each other. A simple and 
effective way is to mark the bottles, jars, etc., contain- 
ing them, with asphaltum varnish, as it will withstand 
acids. 



CHAPTER VI. 



THE USE OF STRIPPING SOLUTIONS. 

It frequently happens that a coating of metal on the 
surface of an object must be removed, either from existing 
imperfections in new work or an old and partially worn 
coating on work that has been brought in to be replated. 
To grind off such a coating is slow, tedious and expen- 
sive, as the several operations of cutting down, polishing 
and coloring must be proceeded with as if the piece 
were new and the amount of metal, if it be silver or 
gold, is also worth saving. To plate such work without 
removing the old deposit makes in most cases a spotty 
and uneven job, as the metal deposits much more readily 
on the old coating than on the bare places, where it is 
most needed. 

The proper course in such cases is to strip, or dissolve 
off the metal from the article, leaving it free and clean, 
so that good, uniform and adherent plating may be done 
without the expense alluded to above. 

89 



90 MODERN ELECTRO PLATING. 

Such solutions are compounded for use in two ways, 
without a battery and with one. The first may be 
regarded as " dips," as they are of the same nature and 
used in the same way, except that the articles remain in 
the solution for a longer time. 

The second class is compounded much as a plating 
solution would be if it were intended to be used with a 
strong current; that is they are compounded with a 
great excess of cyanide and strong alkalies, with a little 
cheap metal in them, and they are invariably used with a 
very strong current of great quantity. The articles to 
be stripped are run as anodes, with a copper, carbon or 
platinum strip used as a cathode. In running work as 
anodes there are certain conditions which make all the 
difference between success and failure. Hanging the 
work in such a bath and allowing it to remain quiet, with 
a moderate current, will simply strip the work, leaving it 
clean but rough; if a strong current be used and the 
work is hung in the ordinary way, the article will be 
stripped, but the surface will be blackened and need 
repolishing; if the articles be suspended by wires so as 
not to touch each other and kept constantly in motion and 
the current be frequently interrupted, the articles will 
come out of the solution bright, smooth and ready to 
color. The work should be immediately rinsed in hot 



MODERN ELECTRO PLATING. 9I 

water and rapidly dried. The wash water may be saved 
and used in keeping up the stripping solution. The 
great utility of such solutions will be at once perceived, 
as the saving of expense in refinishing old work and the 
proper cleaning up of many kinds of new jewelry, etc., 
is extremely important and frequently has even more 
influence upon the plater's reputation as a prompt and 
skillful workman than it does upon his pocket book. 

Stripping NickeL Take a stout stone jar which has 
a cover and place it where the fumes may escape when 
it is being used. Place in it the following mixture, add- 
ing the acids slowly, in the order named: 

Water 2 quarts. 

Sulphuric acid 66° B 16 lbs. 

Nitric acid 4 lbs. 

Allow the mixture to cool before adding the nitric 
acid. The work to be stripped is strung on copper wire 
and immersed in the solution. It should be watched 
carefully and removed and thoroughly rinsed in hot 
water the instant the nickel is dissolved. When pro- 
perly done the work will be bright and clean. 

Stripping Silver* Silver may be removed from cop- 
per or brass articles by dipping them in a mixture of 



92 MODERN ELECTRO PLATING. 

equal parts of fuming sulphuric acid and nitric acid of 
40 B. The copper is not attacked, unless there is water 
in the mixture of acids. Care must be taken to keep the 
solution tightly closed (in bottles or otherwise), as it 
attracts water from the air if allowed to stand open. 

Iron articles are run as anodes in a solution of one 
part of cyanide of potassium to twenty of water, with 
copper or silver cathodes. 

Stripping Gold. Gold may be stripped from copper, 
silver or German silver by dipping in a mixture of 

Fuming sulphuric acid 1 lb. 

Hydrochloric acid (cone.) 2% oz. 

Nitric acid 40 B 1 % oz. 

Care must be taken to see that no water is allowed to 
get into the mixture, or the work will be attacked. This 
mixture works best while warm and the same precau- 
tions as to keeping that have been mentioned in the 
silver stripping solution are also applicable here. 

Iron and steel are stripped by running as anodes in 
cyanide of potassium solution; about ten ounces cyanide 
to one gallon of water, used with copper cathode. 

Stripping Oxides, or Removing the Green, as it is 
often called, is a process which is of great importance 



MODERN ELECTRO PLATING. 93 

in coloring new gold work and should be generally 
understood by the platers who desire to do really good 
finishing on either new or old work of low quality gold. 
During the various operations of manufacture, the 
numerous heatings for hard soldering cause a film of 
oxides, combined with the compounds of the flux and 
the baser metals in the object, to form over the surface 
of the article and in many cases this coating is imper- 
fectly removed by the subsequent pickling and polishing 
it receives. If the article be colored without removing 
this coating entirely, it will work through after it has 
been a short time in use and the purchaser thinks he has 
been swindled. This causes trouble all along the line, to 
retailer, jobber and manufacturer. It is particularly 
prominent with roll plate chains and next to that in rings 
of 6k to 14k quality. Articles of this nature, there- 
fore, should be run as anodes in a solution of 

Carbonate of copper 4 ozs. 

Carbonate of soda 8 ozs. 

FFFF ammonia 8 ozs. 

Water 2 gallons. 

Cyanide of potassium until 16 B. is shown. 

The work is run as anodes in this solution, using a 
strong current and copper cathodes and keeping the 
work continually in motion, as described in the beginning 



94 



MODERN ELECTRO PLATING. 



of this chapter. Properly done, the work will come out 
bright and smooth. An old solution will work better 
than a new one, hence it should not be thrown away, 
but saved and added to from time to time. Care should 
be taken to keep the solution at about i6° B.; under io° 
B. or over 20 B. it will not do good work. 

This solution will be found very useful in cleaning up 
brass or other articles which have become tarnished, also 
in cleaning chains, etc., to be replated, as well as for 
finishing new jewelry. 



CHAPTER VIL 



QUICKING SOLUTIONS FOR CHEAP WORK. 

It sometimes happens that the plater is called upon to 
give a very thin and cheap coating of silver upon articles 
which, from their nature and the metal of which they 
are composed, cannot be polished and prepared for plat- 
ing in the ordinary way; we refer to such articles as 
photograph frames in thin, perforated designs, cast from 
a mixture of tin, lead and antimony or zinc (lead pre- 
dominating in the mixture) trays and various other 
shapes of the metal, all classed by dealers as " Novel- 
ties." These goods are generally brought to the plater 
as soon as cast and must be plated immediately for next 
to nothing. 

Such goods are strung on wires, dipped into hot 
water, then into a hot quicking solution, composed of a 
strong solution of corrosive sublimate (bichloride of 
mercury) and sal ammoniac, which leaves a very thin 
film of mercury on the article; it is then transferred to 

95 



96 MODERN ELECTRO PLATING. 

a silver solution low in silver and strong in cyanide, 
kept in it a moment, rinsed in hot water and dried and 
lacquered immediately. The whole operation must be 
performed rapidly and the work kept constantly in 
motion while in the solutions. The entire process ought 
not to occupy over two minutes. Of course such work 
cannot stand inspection; it is not intended to. Cheap- 
ness and speed are the sole requirements. When doing 
such jobs, the plater must insist that the work be lac- 
quered immediately; it will discolor if allowed to stand 
three or four hours without lacquer. 

Another quicking solution, frequently used on work 
composed of one of the many alloys called " German 
silver " by the various hollow ware concerns, consists of 
a weak solution of potassium-mercury cyanide in water. 
A weak solution of acidulated nitrate of mercury is also 
frequently used on work of this class. 

These solutions are often useful in replating old work 
which has a tendency to refuse to plate in spots that 
have been badly corroded. There is no special rule to 
be observed in regard to strength; the object is simply to 
coat with mercury spots that will not plate without it 
and the less mercury employed to amalgamate the 
surface the better for the work. Such solutions should 
be employed just before the work is put into the plating 



MODERN ELECTRO PLATING. 97 

bath and they should always be followed by hot rinsing 
and the work never allowed to dry. 

Always keep the quicking solutions for the various 
metals separate from each other. A simple and effect- 
ive way is to mark the bottles, jars, etc., containing 
them with asphaltum varnish, as it will withstand acids. 
Covered stone, ten or twenty gallon jars are generally 
used to hold such solutions. 



CHAPTER VIIL 



COPPER AND BRASS BATHS. 

Perhaps the most useful solutions for the man who 
does plating in either a large or small way, are the 
cyanide copper solution and the cyanide brass or 
bronze solution. The acid copper solution often used, 
which is merely sulphate of copper dissolved in water, 
is easily made and used, but has numerous disadvan- 
tages when compared with the cyanide. It will deposit 
faster, but leaves a rough and crystalline surface, unless 
used with current of very low tension, and cannot be 
used on steel, as the latter metal is electrically opposed 
to copper in the presence of sulphuric acid, and sets up 
a local action which throws off the deposit in scales as 
fast as it is formed. 

The cyanide copper solution, on the other hand 
deposits a smooth, even and firm coating, takes equally 
well on steel as on brass or other surfaces, and is 
capable of so many variations that it may well be 

98 



MODERN ELECTRO PLATING. 



99 



regarded as the basis of all brass, bronze and cop- 
per plating. In addition to this, it is the only sure 
means of making a firm deposit of silver or gold 
on steel. Articles of iron or steel should first be 
given a coating of copper, and then the gold or 
nickel will be held firmly, evenly and smoothly, so 
that lighter coatings of the more expensive metals 
wear longer and look better than a thicker deposit 
directly on the steel. 

The old formulae for cyanide of copper solutions all 
recommended mixing acetate of copper with carbonate 
and bisulphite of soda, and then adding potassium cyan- 
ide to the carbonate of copper thus formed. This 
encumbers the bath with a number of useless secondary 
reactions, and makes it liable to readily get out of order. 
It is much better to buy carbonate of copper from a 
dealer in platers' supplies. It is cheaper than the acetate, 
and does not put anything in the solution which is 
unnecessary. 

Formula for Copper* To make the solution, use to 
each gallon of water: 

Carbonate of copper 5 ozs. 

Carbonate of potash 2 ozs. 

Cyanide of potassium (chemically pure) 10 ozs. 



IOO MODERN ELECTRO PLATING. 

Dissolve about nine-tenths of the cyanide of potassium 
in a portion of the water and add nearly all of the car- 
bonate of copper, previously dissolved in a portion of 
the water; then add the carbonate of potash, also dis- 
solved in water, slowly stirring until thoroughly mixed. 
If you have a hydrometer, make your solution to i6° 
B., then put in a small article and test your solution, 
adding cyanide or copper, or both, until the solution 
deposits freely and uniformly. 

This may be regarded as a stock solution, and if much 
work is done, it is best to use it as a basis and make 
others from it, keeping them separate. 

Brass Solutions of any desired color may be made 
by adding carbonate of zinc, in varying proportions, to 
the copper solution. This is done by dissolving about 
one part by weight of carbonate of copper to two parts 
of cyanide of potassium in sufficient water to dissolve 
them and adding same slowly to the copper bath, having 
a piece of work in the tank at the time and noting the 
change of color of the deposit. One part of zinc and 
two of copper will give a yellow brass. 

If the color is to be a light yellow brass, add a little 
carbonate of ammonia to the brass solution. If deposit 
is granular add more cyanide; if slow and dark add 



MODERN ELECTRO PLATING. IOI 

more zinc. If color is too light add more copper car- 
bonate and less current. If, however, the plater desires 
to match colors on repairing jobs, etc., he can get any 
desired color from his brass bath by varying his current; 
a strong current will deposit more zinc than copper, giv- 
ing a paler color of brass in the deposit; and a weaker 
current will deposit more copper than zinc, giving a 
redder deposit. In this way most repair jobs can be 
matched in color, although it is better when doing new 
work to make your solution of the color desired, and use 
an anode of the same color, as by doing so you put the 
two metals into the solution in the same proportion as 
you are taking them out. If you are using copper 
anodes, it is best to buy the electrically deposited anodes 
from a dealer in platers' supplies, as they cost no more, 
are always pure, and deposit much freer and smoother 
than the hard rolled copper for sale at metal houses. 

Management of the Bath. Those who have never 
used the cyanide copper and brass baths may desire some 
additional particulars regarding their management. The 
anodes in such a bath may sometimes show a slight 
greenish coating, consisting of copper cyanide, if the 
bath lacks cyanide. This is soluble in the free cyanide 
that is in the bath, and no traces of it should appear on 



I02 MODERN ELECTRO PLATING. 

the anodes. When the cyanide is used up, this green 
coating thickens up rapidly, and the bath, shortly after- 
wards, stops depositing. In such a case, add cyanide 
(dissolved in water) very slowly, in order not to get in 
too much. When the bath is working properly there 
will be no traces of this green coating, but work put in 
the tanks should be rapidly covered with metal and this 
action is accompanied by considerable evolution of gas, 
which forms a froth over the surface of the solution, if 
the tank is full of work. 

If too much cyanide is in the bath, bubbles of hydro- 
gen will come from the objects to be coated, but no cop- 
per will be deposited, and the remedy is adding car- 
bonate of copper, dissolved in water with a little 
cyanide. 

If either of the above does not give a rapid and even 
coating, the bath needs more metal, and you are likely 
using too small an anode and stripping your bath. The 
remedy is, of course, found in adding more carbonate 
and using a larger anode. 

Any jobbing plater who will make up copper and 
brass baths as above, and work them a little while, will 
not be willing to discard them for anything now known 
to the trade, as in simplicity and ease of working, and 
variety of color, they excel everything else in use. 



MODERN ELECTRO PLATING. IO3 

Heavy Coppering. For coppering before nickeling, 
however, the ordinary cyanide bath will not give the 
best results, as the deposits cannot be made thick 
enough to buff down smooth and solid, so that the 
nickel will hold as if the article were solid copper, go on 
smooth and bright, and stand up under hard usage. 
Bicycle work is probably the hardest test of nickeling 
in use to-day, and next to that comes watchmakers' 
tools, especially lathes. All manufacturers now concede 
that steel work should be coppered before nickeling, and 
while there are many methods of copper plating, there 
is only one way to treat work that is subjected to much 
wear, if you wish the best results. 

A " strike" solution is of no special benefit and does 
not improve your plating; a slightly heavier deposit, 
that will not stand buffing, is hardly any better, as unless 
great care is taken in scrubbing, the nickel will peel off 
in spots, sometimes taking the copper with it. This 
method also requires a very heavy coat of nickel, for 
when it goes to the buffer it requires a great deal of cut- 
ting down before a good lustre can be obtained. The 
best results can only be had by depositing a very heavy 
coat of copper, so that the copper can be buffed bright 
without the steel showing through, and recleaned with 
lime or whiting and a soft bristle brush. By adopting 



104 MODERN ELECTRO PLATING. 

this method of coppering, the work, with a moderate 
current, will stand from two to three hours in the nickel 
bath, and in buffing, a beautiful lustre is obtained with- 
out the use of any cutting-down materials. In buffing 
copper deposited on steel, the rough points, edges or 
corners that the polishing wheel may have left, are 
rounded off, consequently the final nickel buffing 
requires only a slight pressure to bring out a beautiful 
color. 

This method of handling the copper plating is not 
difficult, but it requires close attention, and a copper 
solution built up to suit this work. The copper solution 
should be rich in cyanide, and have just enough copper 
to give a free deposit. To make the solution, fill your 
tank about two-thirds full of water; then dissolve in a 
separate vessel 10 ounces of C. P. cyanide to each gal- 
lon of solution you intend to make, and when dissolved, 
add to the water in the tank and stir; in another vessel 
dissolve 5 ounces per gallon of pure carbonate of cop- 
per. This should preferably be of the moist form, but 
if the moist is not procurable the dry will do. Care 
must be used in either case to see that the copper is 
thoroughly dissolved in the water before adding it to the 
solution. Then add the dissolved carbonate to the 
cyanide in the tank, and stir until it is all taken up. 



MODERN ELECTRO PLATING. IO5 

Finally add 2 ounces of carbonate of potash for each 
gallon of solution, dissolved separately or not, but 
preferably the former. Then make your connections 
to the dynamo, put in anodes and a piece of work, 
and try it. Possibly there will be no deposit, but 
emission of gas instead, or a very slow deposit. In 
this case dissolve more carbonate of copper, and 
add it to the solution slowly, until a good deposit 
is obtained. Should the work blister, and you have 
a strong current on, reduce the current; if you still 
have trouble, add more cyanide. The solution should 
stand at 12 to 15 Baume, and the above formula 
is calculated to bring it nearly there at the start. 
Such a solution has been made and got in good 
running order in two hours, so that any plater 
should have no trouble at all in starting it. 

For anodes you should use the electrolytic or deposited 
copper plates, as they give up copper more freely than 
the rolled plates and keep the solution in better condi- 
tion. The current from the dynamos should be rather 
weak, and must be regulated to suit the amount of work 
in the tanks, which can best be done by having a separ- 
ate switchboard for every tank. 

Let your work hang in the copper tank for thirty 
minutes; should it blister, add more cyanide, reduce the 



106 MODERN ELECTRO PLATING. 

current, and repeat until the difficulty is overcome. 
When the conditions are right; work can be left in the 
copper solution for several hours without showing the 
least signs of blistering. 

Any number of brass and bronze baths may be made 
in this way by dissolving salts of the metals in the 
required proportions with cyanide and water. The 
salts taken are generally the carbonates, as carbonic 
acid is the weakest and is therefore displaced by the 
cyanide with less loss by secondary reactions, as car- 
bonate of potassium may be easily destroyed in the 
bath by adding a little hydrocyanic acid, which drives 
off the carbonic acid in bubbles and leaves the bath 
quite clean and free from secondary reactions, far more 
so at least than can be done when using salts from 
stronger acids. The result is therefore the formation of 
cyanides of the metal in combination with the double 
cyanides of the metal and potassium. Eventually the 
single salts become double salts and then the bath is in 
smooth working order. This is the reason that old 
baths work better than new ones. If a bath were to be 
made from the double cyanide of potassium and any 
other metal it should work well at the beginning, but 
this is too expensive; so the plater makes the cyanide of 
the metal by dissolving the carbonate with cyanide of 



MODERN ELECTRO PLATING. IO7 

potassium, adds free cyanide to the bath, and thus forms 
the desired salt while working. 

In working baths of mixed metals the intensity of the 
current is important, as well as the quantity, and the 
use of measuring instruments is recommended, espec- 
ially to the plater who is working combinations that are 
new to him. 



CHAPTER IX. 



NICKEL PLATING SOLUTIONS. 

Perhaps, of all the solutions in use today, those of 
nickel have undergone the most changes. The writer 
has in his possession seventeen formulae, some of which 
are very complex in their working and could not be 
guaranteed to remain constant for twenty-four hours, if 
used with a modern dynamo and large anodes. To a 
chemist these formulae are very interesting, as they con- 
tain the chemical history of the progress in working the 
metal; but to a workman they are very misleading, 
consisting as they do, chiefly of exploded notions con- 
ceived when batteries, equally unreliable, formed the 
only source of current and expert dodging to favor the 
battery often constituted the entire sum of the opera- 
tor's knowledge. Gradually, however, the citrates, 
chlorides, tartrates, phosphates, pyrophosphates, nitrates, 
etc., have been eliminated and the only bath now in 
use is the double sulphate of nickel and ammonium, 

108 



MODERN ELECTRO PLATING. IO9 

with perhaps the addition of a little boracic acid under 
certain circumstances. 

The Solution* The double salt should be pur- 
chased of a dealer in plater's supplies and care should 
be taken to get it pure and to use as pure water as pos- 
sible. The salt is dissolved by boiling 12 to 14 ounces 
of the salts per gallon of water in a stone jar which has 
never been used for anything else, and rilling up the 
bath with water until a hydrometer placed in it stands 
at 6y 2 ° B to 7° B. This is the method followed for a 
small bath. For a large bath this operation would take 
a couple of days and is not to be thought of, on account 
of the stoppage of the work for so long a time. Large 
baths are made by attaching a hose to a live steam pipe 
and putting a pipe with a steam valve on it on the other 
end of the hose, so that the steam may be readily con- 
trolled. Fill your vat about half full of cold water. 
Then take a large stone jar, perfectly clean and large 
enough to hold several gallons; put a large quantity of 
double sulphate into the jar, filling it perhaps half-full; 
then add some cold water. Next turn on the steam, 
open the valve and allow the live steam to blow through 
a little to take out all dirt, oil, etc., that may be in the 
pipe; then shut the steam off, put the pipe in the jar 



IIO MODERN ELECTRO PLATING. 

and open the valve slightly, so that the steam enters 
and dissolves the salt, which it does very rapidly. 
Dip out the heavy solution as fast as it fills the jar and 
add it to the water in the tank, stirring vigorously after 
each addition of salt, until the solution stands at 6}4° B. 
to 7° B. A workman can dissolve a hundred pounds 
of salt and get a large solution ready in an hour in this 
way, when it would take all day, or even longer, to boil 
and make the solution as first described. 

Anodes. Now, as to the anodes. They are espec- 
ially important in nickel solutions, because the solution 
does not readily dissolve the metal, and this action takes 
place only under the influence of the current. Nickel 
sulphate is not a good conductor of electricity; ammon- 
ium sulphate is a good conductor of the current, but 
exercises no dissolving action upon the anodes. The 
double salt, therefore, is used to combine the two quali- 
ties desired, and the free sulphuric acid, liberated by the 
deposition, immediately passes to the opposite pole and 
attacks the anodes; but the union between the nickel 
and the acid, in the nickel sulphate, is sufficiently com- 
plete, so that there is not enough acid left to attack a 
strip of metal suspended in it without the action of the 
current. If we think over this action and its conse- 



MODERN- ELECTRO PLATING. Ill 

quences, therefore, it will be seen at once that the 
anodes may be left in the solution when no work is 
being done, and this is the general practice, as it saves 
handling the anodes. It is also evident that a large 
anode surface must be maintained to avoid stripping the 
solution and that cast anodes are preferable, because 
rolled anodes are harder and require more current 
power to drive the metal from them into the solution. 
Continuing, we also discover that the anodes should 
be long enough to reach to or beyond the bottom of the 
work, in order to insure good edges; and further, if the 
anode surface is too large and a strong current is used, 
the bath is apt to be rendered alkaline through a partial 
withdrawal of the acid from the ammonium portion of 
the double sulphate. Also, we find that the exclusive 
use of rolled anodes is likely to render the bath strongly 
acid, by robbing the bath of its metal and leaving the 
acid. For these reasons some platers prefer to use 
rolled anodes at the ends of the rods, where the current 
action is strongest, with cast anodes in the middle, 
where it is weaker. This practice however, is being 
gradually given up, as with dynamo current the action 
is more uniform. Rolled anodes are often used for 
small solutions of one or two gallons, as it is easier to 
get them in small sizes. 



112 MODERN ELECTRO PLATING. 

The most suitable distance of the anodes to the 
objects to be plated is from 3^ to 6 inches; nearer 
than than that, the nickeling is apt to be uneven, 
because the metal has not had time to be evenly dis- 
tributed in the solution, while farther away the resist- 
ance is increased and more power is required to deposit 
properly; the current is often regulated in this way 
when other means are lacking. 

Strength of Current. Under all circumstances and 
with all metals, a weak current will give a slow, dense 
and fine grained, hard deposit, while a stronger current 
produces a softer and more open, or even crystalline 
deposit; and as nickel is naturally a brittle metal, it fol- 
lows that a moderately strong current is required to 
avoid a brittle deposit. The most suitable current 
strength is 3^ to 6 volts in the bath, depending largely 
upon the size and nature of the work, and this is gen- 
erally secured by the use of two Bunsen cells, connected 
for intensity, for small work and the use of a suitable 
dynamo for larger operations. The quantity should be 
from .4 to .8 ampere per 15 square inches of surface of 
the object to be plated. This holds good for iron, brass, 
steel and copper, but zinc requires about double the 
above current. 



MODERN ELECTRO PLATING. 113 

Condition of the Bath* A nickel Bath should be 
slightly acid to give a suitable color in the plating. Too 
much acid will cause peeling, and too much alkali 
will darken the tone of the work. The condition of the 
bath in this respect can be readily told by testing with 
litmus paper. If too acid, and the hydrometer stands at 
less than 6%° B., it shows that the solution has been 
robbed of metal, and the remedy is to add carbonate of 
nickel, or sulphate of nickel (generally called single 
salts), by dissolving it in water and adding to the solution 
until the proper content of metal is obtained. If the 
proper amount of metal is in the solution and the bath is 
too acid, it may be relieved by slowly adding carbonate 
of ammonium dissolved in water. If the bath is alkaline 
and more double salt cannot be added, it may be made 
slightly acid with sulphuric or boracic acid, but the 
better way is by slowly adding double sulphate of nickel 
and ammonium, dissolved in water, and temporarily 
reducing the anode surface, if the circumstances will 
allow of it. 

Appearance of the Bath, Anodes and Work* 

The following signs will enable the workman to tell 
whether his current is right, just as the hydrometer and 
litmus paper will tell the state of the solution. Having 



114 MODERN ELECTRO PLATING. 

a slightly acid bath, the objects to be plated should be 
coated thinly with nickel in two, or at most, three min- 
utes, without much gas rising from them. Small bubbles 
coming slowly and regularly indicate regular action. If 
the objects throw out a great number of gas bubbles 
and are instantly covered with a white, thick deposit, 
which soon changes to a dull gray, especially around the 
edges and points or corners, the current is too strong, 
and must be reduced by putting more work in the bath 
or shutting off current. This depositing white and then 
turning gray and finally black is called burning the 
work. If the current is too strong, though not enough 
so to burn the work, the nickel will peel or blister after 
the objects get into use, or in aggravated cases they will 
not stand buffing. 

If there is no deposit on the objects in three minutes, 
and they gradually discolor, turning darker, the 
current is too weak, and more current must be put on, 
or less work be put in the bath. It is a pious idea in 
such cases to make a vigorous search for short circuits. 
The writer could, if he were disposed, give some very 
amusing instances of such happenings, in shops where 
things are allowed to hang or lie on the conductors. 
Such cases often arise where the workman has 
neglected to keep things clean. The drippings of the 



MODERN ELECTRO PLATING. 115 

solution foul the rods as the work is taken out of the 
bath, and this interferes with the current in a marked 
degree. The hooks for anodes and work and the rods 
on which they hang should be kept clean and bright, by 
scouring with fine emery paper. 

Sometimes this trouble is caused by dirty anodes. 
When the current is insufficient to drive the metal 
rapidly into the solution, a dark coating of oxides 
gathers on the anodes, very similar to that which forms 
on the zinc in some forms of primary battery. This 
must be removed by taking out the anode and dipping it 
in water and scratching or scraping it off with an old 
file, cold chisel, or anything of that nature. Keep 
anodes clean. 

The same trouble sometimes arises when the anode 
surface is so small that not enough current can pass 
into the solution. This is the usual result of a mistaken 
idea on the part of the proprietor or foreman, who 
refuses to buy anodes until every scrap of nickel about 
the place has been used up. It is better to sell the worn 
anodes as scrap than to attempt to use them in this way, 
as the loss will be less than that caused by trouble in the 
plating. 

The current is known to be right, and the deposit is 
gray, or streaked, or spotted: The bath is alkaline, or 



Il6 MODERN ELECTRO PLATING. 

has too much metal in it, or too little metal, or contains 
copper. Get your litmus paper and hydrometer. 

If the bath is right and the current is right and the 
same defects appear, the work has not been properly 
cleaned, or has been allowed to dry after cleaning, or 
has been handled with dry or greasy hands after clean- 
ing, so that a trace of grease on the work was turned 
into a waxy gum by the acid of the solution. Absolute 
cleanliness of the work must be maintained in nickel 
plating. 

The deposit is white, but peels under the buff, or can 
be scratched off with the thumb nail: Current too 
strong or bath too acid. 

The work is full of small holes, but the deposit is 
otherwise good: There was a coating of dust on the 
surface of the bath which you neglected to skim off, and 
which stuck to the work when it was put in the bath. 

When a bath gets dusty, or covered with a film of oil 
or benzine, smoke, soot, etc., it should be skimmed off. 
This is accomplished by removing all work, anodes, 
rods, etc., from the tank, and allowing it to stand until 
the film gathers on the surface of the solution; then take 
a sheet of tissue paper by two corners, letting the sheet 
hang vertically, and slowly drop its lower edge on the 
solution at one end of the tank, letting the sheet come 



MODERN ELECTRO PLATING. 117 

down and float on the surface of the solution for about 
half the width of the sheet, Then draw the sheet 
slowly and evenly along to the other end of the tank, and 
allow the balance of the sheet to settle on the solution, 
when, after standing a moment, it may be removed and 
thrown away, taking with it the grease and dust. 
Repeat the operation until the surface remains clean. 
A surprising amount of oil, etc., is sometimes removed 
from a solution in this way. 

Large spots remain uncoated: The pieces of work 
were allowed to touch each other in the bath, or the 
work was not turned about so as to get the air out of all 
hollows and roughnesses in the work. 

The work is coated nicely near the anodes but not on 
the portions further away: The current was too weak, 
or the conducting power of the bath was poor. Some- 
times the spots covered by the hanging wires will not 
be covered in aggravated cases of this kind. Flat 
objects should be suspended between two rows of 
anodes; round objects, or those of irregular shapes, 
should have the anodes placed about them as nearly 
equidistant as possible. 

Doctoring such spotted work is done by removing it 
from the bath and scratch brushing thoroughly, without 
allowing the work to become dry; or, if it cannot be 



Il8 MODERN ELECTRO PLATING. 

scratch brushed, scouring with pumice and cleaning 
thoroughly will do as well ; then return the work to the 
solution. 

With things working correctly, the work will take a 
white, even deposit, which will gradually thicken until 
a dull, bluish luster appears and the work does not take 
a further regular deposit, unless removed from the bath 
and scratch brushed. If allowed to remain in the bath 
without scratch brushing after the color turns into a 
bluish luster, any further deposit is of a dull gray; all 
the metal deposited after this occurs must then be 
polished away to get a bright finish. 

Long Objects, hung vertically, should be turned 
after being coated about half the desired thickness, as 
the nickeling is always heavier at the bottom of a deep 
solution, For this reason it is better to hang the work 
with its greatest dimensions lengthwise of the tank when 
possible. 

The Temperature of the solution is a frequent 
cause of trouble in country shops, and some in cities, 
also, if no provision is made for keeping them warm over 
night in cold weather. The amount of nickel salts that 
water will dissolve and hold in solution, depends largely 



MODERN ELECTRO PLATING. II9 

upon its temperature; the hotter the water, the more 
salt it will hold. If the bath is allowed to go below 6o° 
F., a portion of the salt will crystallize, and be found at 
the bottom of the tank and on the anodes, thus robbing 
it of its metal and making bad work until it is redissolved. 

Density of the Solution* Sometimes the solution 
becomes too dense, on account of the constant removal 
of water, which adheres to the work that is taken out, 
so that crystallization of the nickel salt occurs on the 
anodes. When this occurs, take out the anodes and dip 
them in hot water until the salt is dissolved; then return 
them to their places and add the water to the solution, 
thus saving the salt and reducing the density of the 
solution to its proper standard. 

Sometimes, when baths are being worked very hard, 
the plan of hanging bags of double sulphate salts to the 
rods over night is adopted. This is a simple and easy 
way of refreshing a solution that is being constantly 
robbed, as the salt has all night to dissolve. 

Boracic Acid* We have previously mentioned the 
use of boracic acid. This is sometimes of value when 
the solution becomes muddy and dense, from becoming 
alkaline, so that the deposit is no longer white and 



120 MODERN ELECTRO PLATING. 

tough. The acid is then used in the proportion of about 
two ounces to the gallon of solution, and has the effect 
of clearing up the solution and whitening the deposit. 
It is useful under some circumstances, although baths 
have been run for years with only the occasional addi- 
tion of double salts, and many platers running large 
plants never use anything but single and double sulphate 
of nickel in their baths. 

Thick Deposits* With a bath and current properly 
regulated, work may be left in the tank as long as 
desired and a coating of any desired thickness may be 
produced, if occasionally removed and scratch brushed 
when extra heavy deposits are required. 

Dead Finish* Objects which are not to be polished 
but left dead white, should be rinsed very thoroughly in 
boiling water, then swung in the air, to throw off as 
much water as possible, and allowed to dry spontan- 
eously, and as dead nickel is very readily soiled, it 
should be handled as little as possible. 

Polishing is done with felt or cotton buffs, with a 
little rouge, and then with Vienna lime, using very light 
pressure on the work, and 2,500 to 3,500 revolutions of 



MODERN ELECTRO PLATING. 121 

the buffs. The cleaning after polishing is done with hot 
soapsuds and brush, or hot, weak lye, and a thorough 
rinsing in very hot water, so that the work may be hot 
enough to dry itself immediately, if large; or, if small, it 
is thrown into hot sawdust to dry, and then brushed out 
with a soft brush. 

Black Nickel Plating* Black nickel is, by most 
platers, supposed to be produced by nickeling in the 
ordinary way and then dipping in one of the many 
solutions which give a black color, and afterward 
lacquering. Others dissolve steel filings to the point of 
saturation in hydrochloric acid, and then add one ounce 
of arsenic to the gallon of solution thus formed, and 
then deposit the iron upon the previously nickeled work, 
finishing with lacquer. Another way frequently prac- 
ticed is, to take a quantity of carbonate of copper and 
dissolve it in a portion of the regular nickel solution, 
and add a little arsenious acid. As usually practiced, 
however, these methods are more costly and inferior in 
results to an ordinary black dip. 

It is possible, however, to deposit a coating of nickel 
which shall be of a deep, velvety black and equally hard, 
durable and as thick as the ordinary good nickel plating 
turned out in the best shops of today. Believing that 



122 MODERN ELECTRO PLATING. 

this formula, which I have never seen published, may be 
of considerable use, I give it in full. For each gallon of 
solution desired, take: 

Double sulphate of nickel and ammonia 12 ozs. 

FFFF Aqua ammonia 16 " 

Carbonate of ammonia 2 " 

Arsenic 2 " 

Cyanide of potassium, C. P q. s. 

Water to make one gallon. 

If properly handled this solution is easily made, but 
unless certain methods are followed it can only be made 
with difficulty, if at all. The black color of the deposit 
is due solely to the arsenic, aided a little by the great 
excess of alkali in the bath. If you get in plenty of 
of arsenic you will have a fine velvety black; if less 
arsenic is used the color is brownish, and if little is used, 
the deposit will be powdery and will not adhere. 

Xo Dissolve Arsenic. Arsenic is dissolved in cold 
water with great difficulty (about one part of arsenic to 
eighty of cold water in the course of a week) so we see 
at once that here is our trouble. Arsenic will dissolve 
one part to twenty of water by boiling some hours; this 
is, of course, impracticable also, but it furnishes a hint. 
Certain salts, naturally insoluble in water, are readily 



MODERN ELECTRO PLATING. 1 23 

soluble with the carbonates of the alkaline metals, as 
carbonate of sodium, carbonate of potassium, carbonate 
of ammonium, etc., and as we are going to have ammonia 
in our solution, we take the latter salt in preference to 
the others for our solvent for the arsenic. Again, all 
hot solutions will hold more than cold ones, and the 
stronger our carbonate of ammonia solution is, the more 
arsenic may be dissolved in it. Therefore, we shall get 
along much better by dissolving our arsenic and car- 
bonate of ammonia by boiling in a very little water than 
we would if we took more of it. 

I have been thus particular on this point because the 
use of arsenic is often recommended in various solutions 
which have a tendency to give coarse or granular 
deposits, and its proper introduction into a solution is a 
point that I have never seen explained in any of the 
many works on plating which I have examined. Many 
pounds of it have been put into various solutions only to 
lie as mud on the bottom of the tank, because the per- 
son who recommended it to a plater in difficulty either 
did not know or did not take the trouble to tell him how 
to get it into the solution so that it would stay there. 
And what is true of arsenic is also true of many other 
insoluble salts in more or less frequent use in plating. 
It may be stated as a rule that an insoluble or sparingly 



T24 MODERN ELECTRO PLATING. 

soluble salt may be readily dissolved by combining it 
with another salt more readily dissolved and not antag- 
onistic to the solution, thus forming a double salt, which 
easily dissolves and gives little or no trouble. It is 
usual to select the carbonates for this purpose because 
they are 'more readily attacked by other acids or alka- 
lies, carbonic acid being the weakest of the acids and 
forming weaker combinations with other elements. 

Making up the Solution* The carbonate of ammo- 
nia should be powdered and mixed with the arsenic and 
the two put into a glass bottle and put into a sand bath 
(or the bottle may be put into a water bath if the quan- 
tity is so great that a large bottle is required to hold it), 
then a little water is added and the whole is heated. 
The carbonate of ammonia dissolves first and then dis- 
solves the arsenic. If the carbonate is not all dissolved, 
more water must be added. If the carbonate is all dis- 
solved, and after ■ heating for some time some of the 
arsenic still lies on the bottom, more carbonate should 
be added slowly until the arsenic is all dissolved. In 
this way it is possible to get very strong solutions of the 
insoluble salts. 

The nickel salt may also be dissolved separately in 
some more of the water, at the same time, to hasten 



MODERN ELECTRO PLATING. 1 25 

matters, and when both are ready, put the remainder of 
the water in the tank or jar and add the nickel and 
arsenic solutions and finally the ammonia, stirring thor- 
oughly. When the stirring is completed, the clear 
green of the nickel solution will have turned to a milky, 
reddish blue, or lavender color, and after waiting until 
the color is uniform, we start to clear it by adding cyan- 
ide of potassium. This should be done slowly, stop- 
ping before the solution is perfectly clear and colorless, 
as the changes take place slowly if it is a large solution 
(say 200 or 300 gallons), and if we clear up at once we 
are liable to get in too much cyanide, which would of 
course interfere with the deposit in the same way that 
it does with other nickel solutions. 

When the solution is clear, or nearly so, it is ready 
for the work, which is prepared in the same way as for 
ordinary plating and hung in the bath with nickel 
anodes, using a little weaker current than when plating 
for bright work. A little experimenting will soon deter- 
mine the proper current strength. 

The arsenic gives the black color and firmness to the 
deposit. It is not used up, but remains in the bath a 
long time, sometimes lasting six months or a year with- 
out replenishing. In all other respects the bath is 
handled like an ordinary nickel bath. 



126 MODERN ELECTRO PLATING. 

The deposit should take place rapidly and evenly, a 
sufficient deposit to color being obtained in three or four 
minutes, and if only coloring is desired it should then be 
removed, coming out of the bath a dull black, which 
polishes well and is easily cut through with the buff for 
a "cut through" finish. Leaving the work longer in 
the bath will give a hard, even, durable finish, excel- 
lently adapted for many purposes, and greatly superior 
in color and wearing qualities to any dips or other 
methods now in common use, and at no greater cost 
than that of ordinary bright nickel plating. 



CHAPTER X, 



SILVER PLATING BATHS. 

Chloride of silver, dissolved in cyanide of potassium, 
has long been the standard silver-plating bath. This is 
so from two causes: One is that the use of electro- 
plated ware in silver has been so much more extensive 
than that of any other metal that more attention was 
paid to the solutions, and they were simplified, while the 
formulae for other baths were neglected; the other is 
found in the readily workable nature of the metal, which 
combines easily with the other elements. 

The old formulae all told the workman to start with 
the silver and make his baths from the metal, but it is no 
longer advisable to do so, as the process is tedious and 
troublesome, and will cost him more than it will to buy 
the chloride, with the additional disadvantage of having 
impurities in his bath if he attempts to work up old sil- 
ver, as he probably will. Still, for the information of 
those who desire to know the process, we will give it 

127 



128 MODERN ELECTRO PLATING. 

To Make Chloride of Silver. Take a wide- 
mouthed, two-quart bottle, with glass stopper, the kind 
called " salt mouths " by druggists, and place in it the 
silver you wish to dissolve, which should be bent irregu- 
larly or cut in pieces, so as to present as much surface 
as possible to the action of the acid. Pour in it a quan- 
tity of dilute nitric acid — one part acid to eight of water 
— and place the bottle in the open air, or some place 
where the fumes evolved may escape freely from the 
open mouth of the bottle without fouling the air of the 
room, as they are disagreeable to breathe, and will tar- 
nish bright metal and bleach out wall paper, etc. Add 
the acid, a little at a time, until all the silver is dissolved, 
so as not to get in too much, and thus waste the acid. 
When this is accomplished, prepare a saturated solution 
of common salt (chloride of sodium) and pour it, a little 
at a time, into the nitrate of silver previously formed, 
stirring all the time with a glass rod. The nitric acid 
then leaves the silver and unites with the sodium, form- 
ing nitrate of sodium and freeing the chlorine, which, in 
turn, unites with the silver, forming chloride of silver, 
which gradually falls to the bottom in the form of a 
white powder, when the water becomes quiet. After 
allowing all the silver to settle to the bottom, so that the 
liquid above is clear, add a little more salted water, until 



MODERN ELECTRO PLATING. I2Q. 

no more silver is thrown down, and again allow the 
powder to settle. Then take a rubber tube, and syphon 
off as much of the liquid as you can without disturbing 
the powder. Fill the jar nearly full of water, put in 
the glass stopper, shake the bottle thoroughly, so as to 
wash the nitrate of soda out of the chloride of silver, 
allow the silver to settle until the water is clear, syphon 
as before, and repeat the process two or three times. 
Then dry the powder by standing the bottle in a gentle 
heat until the water has all evaporated. The precipita- 
tion and washing should be performed at night, or in a 
dim light, as chloride of silver is partially decomposed 
by the action of light, turning purple, and these purple 
sub-salts will not dissolve as readily in cyanide of potas- 
sium, thus entailing a loss of silver. It is for this reason 
that the workman is recommended to buy his chloride, 
getting a pure article, and leaving the chemical reactions 
to those who are better prepared to perform them. 
Still, with care and patience, it is not a difficult matter to 
make pure chloride of silver, by using pure chemicals 
and pure silver. If you desire to check up your results, 
you can do so by weighing the bottle and silver before 
you commence and again after the chloride is formed 
and dried in it, which will give you the amount of 
chloride of silver you have obtained. Then get your 



I30 MODERN ELECTRO PLATING. 

druggist to calculate for you the amount of chloride you 
should have, and the difference between the actual and 
theoretical amounts will show the loss from impurities 
in the metal and the washings, etc. Still, the above is 
useful only in working up scrap, or to the experiment- 
alist, etc. 

The Solution for plating should contain three ounces 
of silver chloride and nine to twelve ounces of 98 per 
cent potassium cyanide per gallon of water. It is best 
to make the solution by rubbing the chloride of silver to 
a thin paste with water; dissolving nine ounces of cyan- 
ide in a gallon of water and adding the paste, stirring or 
shaking until dissolved, and then adding cyanide until 
the solution works freely. 

A cyanide bath may be prepared, and the silver 
worked into it with a battery, by using a strong current 
and large anode and small cathode, but it presents no 
advantages over the one made with chloride, and this 
mode is used only when the workman is away from 
ready communication with a dealer in supplies, or his 
bath has become spoiled by accident and he has not time 
to make another in the regular way, and must get his 
work out. In either case the baths should be filtered 
when made, and from time to time while being used, in 



MODERN ELECTRO PLATING. 131 

order to keep them clean; and the dirt from the filters 
should be saved and sent to the refiner, as it contains 
considerable silver. 

The main thing in working a silver bath is to keep 
the proper proportions between the silver, cyanide and 
the current. If there is not enough cyanide in the bath, 
its resistance to the current is greatly increased, and the 
plating becomes irregular in consequence; if there is too 
much cyanide the work does not plate readily, has a 
yellowish or brownish color, and peels in scratch brush- 
ing, or if the excess be very great the object will not be 
plated at all but will give off bubbles of gas. Similarly, 
a weak current requires more free cyanide than a strong 
one. With a little experience the operator will soon 
learn to judge his bath by the appearance of his work, 
and to add silver or cyanide to the bath, or increase or 
decrease his current as required. 

Quantity and Strength of Current. The most 
suitable strength of current for the bath given above is 
one-half volt and the deposition will require one-fourth 
ampere of current for each fifteen inches of surface 
coated. As the Smee cell is one-half volt, it is gener- 
ally used, and the current is closely approximated by 
making the amount of zinc surface immersed in the 



132 MODERN ELECTRO PEATING. 

battery equal that of the objects in the bath, which can 
be done by using two or more cells and coupling as 
many as desired for quantity (all the zincs together and 
all the platinums together) for the plating solution, and 
coupling for intensity (zinc, platinum, zinc, platinum, 
zinc, platinum) for the striking solution, which requires 
a stronger current and a solution weaker in silver. Any 
other battery will do as well, provided the above con- 
ditions are observed. 

Appearance of the Work and Anodes. The 

objects being coated should assume a dull white color; 
if the color is bluish the bath needs cyanide; if the 
white coating forms quickly and changes to a crystalline 
structure, turning dark, metal is wanting. If copper 
and brass articles dipped in the bath are coated with 
metal without any current, there is too much cyanide. 
The anodes should be white when no current is on and 
become gray while plating, changing back to white 
when the current is off. If they remain white during 
the plating, there is too much cyanide; If they remain 
dark when no current is on, the bath needs cyanide. 
When the bath needs cyanide, it should be dissolved in 
water and added a little at a time, to avoid getting in too 
much. When silver is needed, a little chloride should 



MODERN ELECTRO PLATING. 133 

be rubbed to a thin paste with water and added, or the 
quantity of anode surface should be increased. Unless 
correcting the bath, the surface of the silver anode 
should equal that of the work, as otherwise the solution 
is constantly being stripped, and chloride must be as 
constantly added to maintain its proportions, which is 
more costly than using larger anodes. 

Striking Solution. The striking solution is made 
by taking a quart of the plating solution and adding 
three quarts of water and three ounces of cyanide. 
It should be worked with a strong current as 
above described, and should give a firm, even and very 
adhesive coating of silver, of a yellowish color, giving 
off gas freely from the object in the bath. This yellow 
coating is used merely as a binder between the object 
and the silver plating, hence the articles are placed in 
the striking solution after being cleaned, and trans- 
ferred to the regular bath as soon as they become thinly 
and thoroughly covered with the striking coat, 

Correcting the Bath, After working a silver 
bath for some time it will gradually thicken and also 
become dirty, owing to dust from the atmosphere and 
other impurities which have been carried into the bath 



134 MODERN ELECTRO PLATING. 

with the work, and also with the cyanide and silver 
which have been added from time to time in correcting 
the bath. 

When silver chloride is added, it is attacked by the 
free cyanide and decomposed, forming cyanide of silver 
and chloride of potassium. The latter is a readily solu- 
ble salt and remains in the solution. When the cyanide 
used contains potash, instead of being chemically pure, 
the potash remains in the solution and slowly turns into 
carbonate of potassium by the action of the air. When 
this takes place to a considerable degree the silver 
deposited becomes dull, porous and spongy, owing to 
the interference with the current by the increased resist- 
ance of the bath. This is corrected by slowly adding 
hydrocyanic acid until the precipitate in the solution is 
nearly all dissolved, and the deposit is once more firm 
and of the proper color, when the bath should be filtered 
to remove the dirt and other impurities. Always save 
the residue from filtering and send to the refiner. 

Great care must be exercised in handling any bath 
containing cyanide, as it is a deadly poison. Be very 
careful never to drink from any vessel that has been 
used in handling cyanides (or prussiates) in any way, or 
to handle them with cut or scratched fingers. Never 
fill a syphon by sucking, for the same reason; it has 



MODERN ELECTRO PLATING. 135 

killed many a man who was too careless to do his work 
properly. The way to fill a syphon is to plunge it in a 
pail of water, or fill it from a hydrant or wash bottle, 
and then when the tube is full of water, close the two 
ends firmly with the fingers and place one in the solu- 
tion to be syphoned, and the other in the vessel to which 
it is to be transferred; then open the upper end of the 
tube and finally the lower one. If handled in this way 
large tubes may be used and syphoning rapidly done. 

If the bath becomes too foul to be corrected in this 
manner, take it into the open air where the gas can 
escape freely, and add hydrochloric acid until the silver 
has all been precipitated as chloride. Draw off the solu- 
tion from the precipitate with a syphon, as described in 
making chloride of silver; wash it thoroughly, dry it and 
mix with twice its weight of carbonate of soda, and half 
its weight of pulverized charcoal. This mixture is then 
fused in a crucible and allowed to cool, when on break- 
ing the crucible a button of silver will be found in the 
bottom. This may then be redissolved in nitric acid 
and turned into chloride as previously described, or used 
as metal anodes in forming a new bath. 

Amount of Silver Deposited. The following table 
shows the amount of silver generally deposited upon 



136 



MODERN ELECTRO PLATING. 



plated ware, and may be regarded as sufficiently close 
to serve as a general standard: 

AMOUNT OF SILVER DEPOSITED ON PLATED-WARE. 



ARTICLES. 



PWT. 
SILVER. 

Table Knives per doz. 10 

Desert and Tea Knives " 8 

Butter Knives " 10 

Spoons, Table " 10 

Desert " 8 

Tea " 5 

" Mustard " 4 

Salt " 4 

Egg " 4 

Ladles, Soup " 36 

Forks, Dinner " 10 

" Desert " 8 

Nut Picks 

Napkin Rings " 6 

Tea Sets per piece, 20 



Pots or Urns, Tea 

" Coffee... 

" Small .. . 
Pitchers, Ice 

Wine 

Milk 



ARTICLES. 



PWT. 



Cups, Cream per piece, 

" Childs " 

Cups, Childs, gold-lined " 
gold 

Stands, Fruit " 

Celery.- " 

" Wine " 

Baskets, Cake 

Card 

Tureens, small •.. 

" large " 

" extra large .. 

Castors, small " 

" large " 

Butter Dishes 

Syrup Jags " 

" " with stands " 

Call Bells " 

Watch Cases, 10-18 Size " 

" " Open Face " 

" Dials.- 



The cost of depositing silver with a battery is 
from $1.00 to $1.25 per ounce of silver deposited; of 
this 25 cents will be for battery, and the balance for 
metal and maintenance of solution, etc. This does not 
include the cost of preparation of the work or its subse- 
quent burnishing, lacquering, etc. 



MODERN ELECTRO PLATING. 137 

Sectional Plating is done by placing an article in the 
bath in such a manner that only the portions subject to 
the greatest wear touch the solution. After the desired 
extra thickness has been deposited, the whole article is 
then immersed and plated as usual, and the margins of 
the extra coating, which are plainly apparent when the 
article comes from the bath, disappear in the burnishing. 

Turning Yellow* If the objects come from the bath 
a pure white color, and afterward turn yellow in the 
air, this is due to the formation of basic silver salts in 
the deposit. In such a case dip the articles for a few 
minutes into a hot solution of cyanide, which dissolves 
the salts, and then into hot water, after which they may 
be burnished. 

The Double Cyanide Bath, Partly because it is 
more convenient, and partly because it is erroneously 
supposed that it requires less cyanide of potassium, a 
great many amateurs and professional operators in plat- 
ing establishments make use of the chloride of silver in 
making the silver solution. Those who have once used 
the double cyanide solution for electric deposition of 
silver, will never use any other for large baths. We 
shall, therefore, give a few hints pertaining to the mak- 



138 MODERN ELECTRO PLATING. 

ing and the use of a double cyanide of silver solution. 
To begin, take the prepared nitrate of silver, and do 
not attempt to make it from the grain or metallic silver, 
as you can buy it cheaper from the manufacturers of 
chemicals than you can possibly make it yourself. 

In making, say, one gallon of solution, dissolve 2 
ounces of nitrate of silver in plenty of water, say, two 
gallons; then dissolve in a separate vessel, having a 
spout, about 4 ounces of cyanide of potash, in about 
one-half gallon of water. From this cyanide solution, 
pour a little at a time, while stirring, into the nitrate of 
silver solution. Continue this as long as a precipitate 
is formed. Pour the cyanide in more cautiously, and 
in smaller quantities, as you proceed, to prevent getting 
in an excess of cyanide, which would dissolve the pre- 
cipitated silver. When the precipitate is no longer 
produced readily, give the solution a thorough stirring 
and let it settle for about five minutes; then pour a few 
drops of the cyanide solution into the nitrate solution, 
and if no white precipitate is formed, stop; any further 
addition of the cyanide will cause a loss of silver. Now, 
if the vessel is large enough to permit it, add more water 
so as to render the solution less dense, and thereby 
facilitate the settling of the precipitate. Let it stand 
until thoroughly settled, so that the liquid above is clear, 



MODERN ELECTRO PLATING. 1 39 

and then pour off the clear liquid and add a new lot of 
fresh water; let it settle again, and pour the liquid off the 
precipitate. Repeat this washing two or three times, 
and throw the moist precipitate upon a filter, and once 
more throw fresh water upon the same, so as to render 
it perfectly pure. Then, place the precipitate into about 
one-half gallon of " soft " water (if possible, rain, or 
distilled water), and add cyanide of potash in solution, 
until all the precipitated silver is dissolved, and making, 
with the cyanide solution, about one gallon. Add about 
i ounce more of free cyanide to the solution, when it 
will be ready for use. 

In making a small solution, I would suggest that the 
workman buy the cyanide of silver and dissolve the same 
in water and cyanide of potash; in other words, take i 
gallon of water, 2 ounces of cyanide of silver, 4^ ounces 
of cyanide of potash; mix and stir them thoroughly, and 
filter through closely woven muslin. 

Strength of the Current* The intensity of current 
required for the deposition of silver is about one volt. 
The articles to be plated should never boil, as in copper 
and brass solutions. Adjust the surfaces of your cathode 
to that of your silver anodes, and the two to the strength 
of your current, to prevent a so-called burned deposit. 



I4O MODERN ELECTRO PLATING. 

Use chemically pure cyanide only. For the electro 
plating of spoons, knives and forks, richer solutions, say, 
3 ounces of silver to the gallon, are used. Two ounces 
of silver to the gallon, make a fairly rich solution. Let 
your anode surface be nearly that of your cathode 
surface, so as not to impoverish your solution, and adjust 
your current so as to prevent boiling at the cathode. 



CHAPTER XL 



GOLD AND ITS USE IN PLATING. 

Gold is perhaps as little understood by the average 
plater as any metal with which he has anything to do 
and its use has apparently drifted nearly altogether into 
the hands of a few specialists, who guard their secrets 
with jealous care and easily displace any would-be com- 
petitors by their superior knowledge, which enables them 
to turn out more work of a better appearance with very 
much less use of the precious metal. And when we 
consider the great cost of the metal and reflect upon the 
care that is taken to save and recover it from the wastes 
by all manufacturers who use it, it will be readily seen 
that the specialists' position is a very strong one and that 
a little gold saved is an important item, and when we 
further reflect that there is no standard of weight of 
metal deposited on certain articles, as there is in silver, 
and that, on the contrary the less gold there is to main- 
tain its appearance in most work, the better, it may be 



I42 MODERN ELECTRO PLATING. 

readily concluded that the man who can spread the least 
gold over the most surface, and make it stick, has an 
immense advantage over his competitors in nine-tenths 
of the work done now-a-days. 

In addition to this, no other metal gives so great a 
variety of shades of color, hardness and wearing qualities, 
as does electro-deposited gold. A bath made up of 
chemically pure chloride of gold and used with fine gold 
anodes will give anything from a pale 16 karat color up 
to 24 karat yellow, or any number of shades of a coppery 
red, according to the temperature of the bath and the 
strength of current used. Each of these shades will vary 
in its hardness, speed of deposition and wearing qualities. 

Furthermore, a gold bath differs from all other metals 
in the important particular that, while in all other solu- 
tions care is taken to keep the strength up by using 
anodes equal in surface to that of the work immersed in 
them, the opposite is the rule in gold work (on account 
of the cost), and as the surface of the work put into a 
gold solution is frequently ten, fifteen or twenty times 
that of the anode (particularly in gold lined hollow ware) 
it follows that the solution is being constantly robbed 
and must be as constantly doctored if in steady use. 
This matter is further aggravated by the extreme disin- 
clination of gold to form chemical combinations with 



MODERN ELECTRO PLATING. 1 43 

other substances, making it correspondingly easy to 
release the metal from those combinations, and thus 
causing it to deposit with great speed, with a compara- 
tively weak current. 

From these considerations it will be readily seen that 
there is abundant reason for the existence of the special- 
ists in gold work and hence we have platers who cannot 
color, colorers who never plate, and finishers who know 
but little of plating or coloring as practiced by the two 
first mentioned, 

Nature of the MetaL Gold is one the most malle- 
able and ductile of the metals; when pure it is of a yel- 
low color, becoming paler by the addition of silver and 
redder by the presence of copper. Unless specially 
refined, it always contains traces of these metals, which 
is the reason gold baths made by running an anode in a 
cyanide solution will not give as rich a color as those 
made with pure chloride of gold. The specific gravity 
of gold is from 19.35 for cast, to 20.2 for rolled, and 
19.2 for precipitated powder. In melting it exhibits 
a sea green color. It readily alloys with most metals 
and is seldom free from some of them in nature. The 
most common of these are mixtures of silver and 
copper, but tin and lead form alloys very difficult 



1^4 MODERN ELECTRO PLATING. 

to separate from gold and render it hard, brittle and 
unfit for working. This is not apt to trouble the 
plater unless he attempts to work up old gold, when he is 
almost certain to get into trouble from the solders, etc., 
contained in the old metal. 

Chloride of GolcL Pure gold preserves its luster in 
the air and is not acted upon by any of the acids, such 
as sulphuric, hydrochloric, nitric, etc. It unites readily 
with chlorine and then, as chloride, with the mixtures 
which generate the chlorine; therefore if we take hydro- 
chloric acid, mix with it enough nitric acid to slowly 
destroy it (thus liberating the chlorine), and place in it 
some gold foil, wire or sheet, the chlorine liberated from 
the acid will unite with the gold and -form chloride of 
gold, which will remain in the solution. This mixture of 
acids is known as aqua regia. The formula is : 

Nitric acid i part. 

Hydrochloric acid 2 " 

In dissolving the gold it is necessary to have 

Gold 10 parts. 

Aqua regia 15 " 

The proportions given are the exact quantities needed. 
In practice, however, a little more aqua regia is taken in 
order to allow for loss by evaporation. Cut the gold into 



MODERN ELECTRO PLATING. I45 

thin strips or ribbons and bend or crumple them in such 
a manner that they will expose as much surface as possi- 
ble to the action of the acids; place them in a thin Flor- 
ence flask and pour in the aqua regia; then set the flask 
away in a warm place (7o°F. to oxrF.), to dissolve, and 
gently shake it occasionally. Do not cork the flask, as 
the escaping gas is liable to break it. Ventilation should 
also be provided for, as the chlorine will tarnish every- 
thing it comes in contact with. Or, if necessary to 
hasten the operation, the flask may be placed on a sand- 
bath and gentle heat applied, taking care that the mix- 
ture does not boil. When all is dissolved the liquid will 
be of a reddish brown color, getting darker as the sur- 
plus acid and water are driven off by the heat, when the 
heat should be lessened to avoid danger of " burning " 
(precipitating the gold in the form of a brown metallic 
powder and thus spoiling the operation), making it neces- 
sary to add more aqua regia and start over again. Hav- 
ing continued the heat gently until the liquid commences 
to thicken, withdraw the flame and allow the heat con- 
tained in the sand bath to continue the operation. If 
sufficiently evaporated it will crystallize on the sides and 
bottom of the vessel, leaving a little thick, syrupy liquid 
in the center. The liquid is poured off into another flask 
and evaporated a little further, when it, too crystallizes 



I/j.6 MODERN ELECTRO PLATING. 

and the chloride is ready for weighing into the solution. 
If extreme purity is desired it is dissolved in water and 
again evaporated before using. 

From the above description it will readily be seen that 
taking into account the necessity of starting with pure 
acids and pure gold, it will not pay a plater to attempt to 
make his chloride, as unless in some emergency, it will 
be cheaper to buy it. The operation is given, however, 
in order that the plater may have a clear idea of the 
process if it should become necessary to use it. 

Percentage of Gold in Chloride. Pure chloride of 
gold contains 65 per cent of gold and 35 per cent chlo- 
rine; therefore, there are 312 grains of gold in an ounce 
of chloride of gold. It is well to remember this fact, as 
it affords a ready means of determining the proper 
amount of chloride to add in making up baths from 
formulae which give gold only in the formulae, and vice 
versa. 

Varieties of Gold Solutions, We now come to the 
formulae for the baths, and here we will note a wide 
divergence in practice, as to the amount of metal they 
contain; they vary from 15 grains of gold per quart up 
to 320 grains per quart, according as they are to be used 



MODERN ELECTRO PLATING. 



147 



hot or cold and with a battery or dynamo current and 
also according to the color required. 

Proportions of Cyanide* They also vary in the 
proportions of cyanide used, the lighter baths requir- 
ing more free cyanide and the heavier ones less. This 
cyanide question is largely settled by the current used, 
a current of 3 volts requiring about ten per cent of free 
cyanide and a stronger current less until we reach about 
8 volts, when the excess of cyanide should be very slight. 
The reason is that the cyanide reduces the resistance of 
the bath, allowing the current to pass more readily, and 
as the metal also performs the same office, we shall 
interfere with the color and texture of our deposit if the 
due proportions are not observed. Too large an excess 
of cyanide yields deposits of an ugly, pale color, as if 
there were silver in the bath, while too great a quantity 
of metal has a tendency to cause a red brown deposit if 
the current is not kept of suitable strength. 

Hot baths, for hot gilding, work with from 11 grains 
to 20 grains of gold to the quart and a considerable 
excess of cyanide, while those for cold gilding and pla- 
ting should contain not less than 60 grains per quart and 
may have 320 grains. The latter high content of gold 
is used with a dynamo current where great speed is 



I48 MODERN ELECTRO PLATING. 

required and the work is simply dipped in and taken out 
again, the deposit taking place almost instantly. 

Color of the Deposit* There are two ways of 
varying the color of the deposit. One is by varying 
the temperature and is generally practiced with hot baths, 
in which a solution of 90°F. gives a pale color; I20°F. 
to i30°F. gives a fine yellow, while increasing the temp- 
erature to i40°F. gives a reddish color. The second 
method is that practiced in cold baths and it is accom- 
plished by varying the current. A small current gives 
a pale color; a medium current a fine yellow and a large 
current redder tones. A little experience will enable 
the operator to match colors readily either way, but he 
must be cautious about getting too much gold on, as the 
increase of temperature or current strength will hasten 
the deposit of the metal in a marked degree, making it 
necessary to correspondingly shorten the time the work 
is in the bath. Lastly, the operator must determine 
whether the work is to come out of the bath bright or to 
come out dull and be brightened under the brush (or left 
dull), and choose his bath accordingly. 

Hot Baths are generally supposed to give a closer 
texture and finer grained deposit than cold baths, owing 



MODERN ELECTRO PLATING. I49 

to the superior conductivity of the bath and its greater 
speed of operation with a weak current. For this rea- 
son they are generally preferred for "finishing" large 
quantities of cheap work, where the thinnest possible 
layer of gold of the exact color of the metal beneath it 
is desired, as in the sliding tubes of French opera glasses, 
brass rims on opticians' trial lenses, brass uniform but- 
tons and other articles which rely about equally on a thin 
coating of gold and a subsequent coat of lacquer to pro- 
tect them, and which must be handled in bulk with great 
speed, being seldom in the bath longer than five to ten 
seconds. Another important advantage on such work 
is that hot solutions readily dissolve any greasy matter 
or film of oxide left on the work through careless treat- 
ment and thus secure a more nearly uniform coating on 
work which would otherwise have to be handled with 
much greater care and consequent expense in the pre- 
liminary buffing and cleaning. 

Stock Solutions* Hot solutions, however, have 
the drawback of requiring constant doctoring, where 
large quantities of work are being handled, on account 
of the surface of the work being greatly in excess of 
that of the anode and also owing to the fact that hot 
cyanide has very little effect on metals, while cold 



150 MODERN ELECTRO PLATING. 

cyanide will dissolve them readily. The usual practice 
in such places, therefore, is to keep a strong stock solu- 
tion of gold ready to add to the bath. This is made by 
dissolving one part of chloride of gold and one (or one 
and one-half) parts of cyanide of potassium separately 
in distilled water and then mixing the two solutions, the 
resulting cyanide of gold being all ready for work as 
soon as put in the bath. Of course it will be readily 
understood that, as the object is to have a strong stock 
solution of gold cyanide, it is advisable to use as little 
water in dissolving the gold and cyanide as will suffice 
to keep the gold cyanide in solution in the stock bottle. 
A little reflection will also show that the gold disappears 
from the bath much more rapidly than the cyanide, so 
that it will be prudent to use as little cyanide in the 
stock bottle as will dissolve the gold, or we shall pre- 
sently have too much cyanide in the bath. 

In working hot baths hot water must be added from 
time to time to make up for that lost by evaporation. 

Hot baths are also employed by many on the score of 
cheapness, as they work with so much less gold in the 
solution, as previously stated, and also because they may 
be advantageously used with batteries. When using 
gold solutions of many different colors for fancy gilding 
the saving is considerable. 



MODERN ELECTRO PLATING. 151 

Cold Baths are, however, preferred in manufactur- 
ing establishments, where power is readily accessible 
and dynamos can be used to supply a steady current of 
uniform strength and any desired quantity. In such 
cases uniformity of color and thickness of the deposit 
are the chief objects desired and these are best secured 
by having large baths made up to special colors and 
maintained by anodes of the same quality of metal as is 
contained in the bath, it being better to put the money 
into large solutions, rather than run any risks of lack of 
uniformity in thickness and color of deposit on articles 
which are turned out by the hundred or thousand and 
afterward carded or boxed in dozens from an indiscrim- 
inate heap, as in such cases any difference in the deposit 
would be sure to show when the goods were carded or 
boxed. Hollow ware, too, is gold lined with cold solu- 
tions on account of the greater convenience in handling 
and the fact that it is sometimes undesirable to heat 
them after they have reached a finished stage of manu- 
facture. Heavy plating of watch cases, chains, etc., 
is generally conducted in cold baths, using plenty of 
current of low voltage and conducting the work slowly, 
in order to secure a uniform and hard deposit. This, 
however, should not be confounded with coloring or 
finishing cases, where the very opposite is the rule. 



152 MODERN ELECTRO PLATING. 

Strength of the Current. In cold gilding, as in 
other plating, the operator must always remember that 
a weak current of suitable quantity to deposit uniformly 
will give a close-grained, hard deposit, while a strong 
current, even of less quantity, will give a coarser, more 
open texture, which increases in the size of the grain 
with the strength of the current until it becomes cry- 
stalline and finally becomes a powdery deposit, which 
refuses to adhere. This applies to the strength of the 
current, independently of its quantity, and should be 
distinguished from the action of too great a quantity of 
low voltage, as the latter simply darkens the work until 
it " burns " it, by causing a powdery deposit as before, 
without causing anywhere near as great an increase in 
the size of grain of the deposited gold. 

Larger and cold baths also require a greater current 
strength than smaller and hot baths, as the quantity of 
surface of work exposed is usually greater and the dis- 
tance between anodes and work is also greater, thus 
causing more resistance in the bath which it takes more 
current to overcome. 

Regulation of the Current. When the operator 
is using current from a dynamo the supply is always 
ample and regulation becomes merely a question of 



MODERN ELECTRO PLATING. 1 53 

shutting off more or less current according to circum- 
stances; this is done as follows: A wire that is just 
large enough to carry the most current that will be 
required is run from the dynamo to the bars on top of 
the vat containing the gold solution. If a resistance 
switch can be afforded it should be placed near the 
vat, on the positive wire from the dynamo, so that 
the operator may reach the switch to adjust the current 
without leaving the bath. The current should not be 
over 6 volts and 3 to 4 volts is better. If the current is 
too strong, it may be run through a spool of double cov- 
ered office wire to cut down the strength. Then the 
anodes should be attached to the bar of the vat by a 
much smaller copper wire, leaving it long enough so 
that the anode may be plunged partially or entirely into 
the solution at will. Now, the greater the anode sur- 
face immersed, the less the resistance will be and the 
more current will pass, therefore the amount of anode 
surface immersed will govern the current. 

When handling large surfaces, especially in cold solu- 
tions, it is desirable that the gold shall immediately cover 
the work in order to protect it from the free cyanide of 
the bath and save fouling the solution; therefore the 
workman first connects his wire from the bar to his 
work, then immerses it in the solution and immediately 



154 MODERN ELECTRO PLATING. 

takes the anode, plunges it far enough into the bath to 
get sufficient current and moves it about near the parts 
of the work that do not become coated immediately, 
thus favoring those parts. When the work has become 
evenly coated all over with gold, the anode is with- 
drawn until the current is right to produce the desired 
color and the deposition then proceeds more slowly. 
This method of current regulation by the anode is the 
same for both cold and hot solutions and for dynamo and 
battery currents; but in working with a battery (lining 
hollow ware for instance) the workman should always 
make sure that his solution is rich in gold and that he 
has current enough to coat evenly at the start, other- 
wise the coating will be uneven and may not stick at 
all; so most workmen prefer to be on the safe side and 
couple up cells enough to give plenty of current of the 
proper strength. Sometimes in lining water pitchers or 
other deep vessels, in which the solution is poured into 
the vessel instead of putting the vessel into the bath, it 
will be found that the anode is too small to move about 
as described; in such cases the wire from the work is 
unfastened and moved about on the outside of the 
pitcher in close contact with it, so as to control the 
deposit by favoring those portions that are slow. This 
method, while not equal to the other, will aid matters. 



MODERN ELECTRO PLATING. 1 55 

Color of the Deposit, In working cold baths, if 
the color is too pale, while the deposit is good, there is 
either not enough current or too much free cyanide for 
the amount of gold in the bath. Put on more current 
in such a case and if that does not remedy the color add 
more gold cautiously until the due proportions of gold 
and cyanide are restored, If the color is too red, reduce 
the current and if that does not fix the color there is too 
much gold and not enough cyanide in the solution, so, 
of course, we add cyanide and water slowly. 

In working hot baths we have another factor (the 
temperature) to consider. Below 120° F. the color 
should be pale; 120 to 130 F. should give a line yellow; 
140 to 170 F. gives red shades. Warm up a ther- 
mometer, so as not to break it, and put in the bath. If 
the temperature is right, then change the current and 
finally the solution. 

By always examining the current first and then the 
bath (in cold baths) and temperature, current and bath 
in the order named in hot baths, the workman will run 
no risk of getting a good bath out of order. 

Any work should be immediately coated with gold on 
being placed in the solution. If the deposit takes place 
only on the parts nearest to the anode, or if the work is 
coated and the gold is afterwards dissolved off again, the 



156 MODERN ELECTRO PLATING. 

current is too weak or there is too much free cyanide. 
Change the current first; then look after the bath. If 
the deposit takes place too rapidly it will be irregular, 
patchy or spotted; then the work should be well scratch 
brushed and the current changed and finally the bath as 
before. 

Formulae for Gilding and Plating* Platers who 
have thoroughly understood our remarks on the man- 
agement of gold baths, will have no need of any form- 
ulas for gold baths, as they will be able to make or fix 
up any required baths from their knowledge of the 
metal, cyanide and current, without any special formulas. 
Still, we will give here a few of those in most common 
use, with observations on their nature and use, for the 
benefit of those who may desire to experiment a little 
with them, to learn the capabilities of each. 

Baths for Steel and Iron. In gilding direct on steel 
and iron (without a previous coating of copper) the 
baths should contain less gold than for other metals, it 
being generally sufficient to take a portion of the regu- 
lar bath and add water and a little more cyanide of 
potassium, until the desired color is obtained. Too 
much gold gives a dark deposit, which does not adhere 



MODERN ELECTRO PLATING. 1 57 

as well to the steel. If the workman happens to be 
using a bath that is low in gold, he can usually obtain 
the desired color in his regular bath without trouble by 
using a weak current. The deposit should start slowly 
on steel, or it will not adhere well. 

Bath for Bright Gilding* A formula? for depositing 
a coating of gold that will be bright after rinsing and 
brushing, is as follows: 

Potassium Ferrocyanide 2 ozs. 

Carbonate of soda 2 ozs. 

Fine gold (as chloride) 5 pwts. 

Water 1 gal. 

Dissolve the ingredients separately in portions of the 
water; add the soda solution to the potassium solution, 
and heat to the boiling point; then add the gold solution 
and boil for about fifteen minutes. After cooling add 
sufficient water to make up for that lost by boiling, and 
filter. This gives a fine bright color on all metals, even 
iron and steel, if used with a current of about three to 
four volts. 

Carat Solutions* Dissolve 14 ounces of cyanide of 
potassium to each gallon of water; heat to I20°-I40° 
F., and suspend two anodes of the desired quality of 



158 MODERN ELECTRO PLATING. 

gold in the solution, and run them until the solution 
contains sufficient metal to deposit well. In making 
solutions by the battery process, the operator should 
change the depth of his anodes from time to time, 
as they are liable to be cut through at the water line 
unless this is done, the action being greatest there. 
The anode to be stripped should also be much larger 
than the other. 

Red Gold Solutions. If the operator happens to 
have a cyanide of copper solution, he can make up vari- 
ous shades of red gold solutions by mixing various quan- 
tities of the two solutions. The color depends on the 
relative quantities of metallic gold and copper in the 
solutions. Ten per cent of copper gives a pale red; 20 
per cent of copper a fiery red, and 30 per cent gives a 
deposit of a copper color, but which will not tarnish; or 
the solutions may be made by dissolving cyanide of cop- 
per in water and adding it to the gold solution. If the 
cyanide is not at hand, dissolve carbonate of copper in 
cyanide of potassium, with a little water, and the same 
end is obtained. They should be worked with anodes 
of the same composition as the solution, or a fine gold 
and a copper anode of proper proportions may be hung 
side by side in the solution. 



MODERN ELECTRO PLATING. 1 59 

Green Gold* Increasing the quantity of silver in a 
carat gold solution will give greenish shades, if the cur- 
rent is properly regulated. It is not easy to do such 
work uniformly, however, as the current has to be 
nicely regulated according to the surface of the work. 
Too weak a current will deposit more silver than gold, 
and too strong a current will deposit more gold than 
silver, making a yellowish instead of a green color. 
With a resistance box and a constant source of current 
a very pleasing green-gold may be obtained, which will 
do a great deal to brighten up medal work especially if 
used in connection with red shades. 

Pale Straw Colored Gold* This is obtained by 
adding to the ordinary gold solution a small quantity of 
cyanide of silver, previously dissolved in water, and 
working the solution cold with a weak current and small 
anode, keeping the work constantly in motion, to 
brighten the color and seGure a uniform deposit. 

Rose Colored Gold* This is obtained by adding 
suitable quantities of copper and silver cyanides to 
the gold solution; but it also requires close attention to 
the proportions of current and work. Hot baths are the 
best for this solution. 



l6o MODERN ELECTRO PLATING. 

Nickel and Gold Solutions. Probably one of the 
most useful alloys of gold for platers is that with 
nickel; besides being cheaper it has a much richer color 
than a solution containing gold and silver and gives a 
correspondingly better appearance to the finished work, 
or, which is the same thing, permits a much larger pro- 
portion of the cheaper metal to be used for a carat 
color. In addition to this it is much harder and wears 
better in consequence on large flat surfaces, or edges 
exposed to wear, such as watch cases, chains, harness 
trimmings, etc. It is in use in many of the case fac- 
tories and a number of the large finishing shops of the 
East. Like the solutions given above, it is made by 
adding cyanide of nickel to the ordinary gold cyanide 
bath and working with anodes of the same composition. 
The solution may be made by dissolving from anodes, 
as given above for gold, or it may be made by dissolving 
double sulphate of nickel and ammonia in water to 
which cyanide of potassium has been added, boiling to 
expel the ammonia, and then adding the solution to the 
ordinary gold solution. Carbonate or chloride of nickel 
may also be used, dissolved in cyanide as above. We 
have not given proportions, as very few use any exact 
formula; in a general way it may be stated that the 
usual practice is to use 30 parts of nickel to each 100 



MODERN ELECTRO PLATING. l6l 

parts of gold. It requires a nice balancing of current 
and solution to get a bright color, the nickel working 
best with a strong current and the gold with a weak 
one. 

Proportions of Metal in Various Salts. In mak- 
ing solutions from anodes the proportions take care of 
themselves; but in making them from salts it will be 
necessary to ascertain the amount of metal in each salt 
and proceed accordingly. If the workman is not able 
to do this for himself, he should get a chemist to calcu- 
late for him the various quantities of metals in the 
chemicals he is using and make a list of them for 
reference; then if, for instance, he desires to make up a 
gold solution containing i penny-weight of gold to the 
gallon he would know exactly how much chloride of 
gold he needed for that solution. By proceeding in this 
way he will avoid guess work and save much valuable 
time and expensive materials. This is extremely impor- 
tant when it comes to handling large solutions or a great 
number of small ones, each of different composition. 

Effects of Varying Strength of Current in Depos- 
iting Alloys* In working any solution containing more 
than one metal, it must be borne in mind that each metal 



1 62 MODERN ELECTRO PLATING. 

has a certain current strength at which it will deposit 
most freely, and that if the work be done with this 
strength of current, that metal will be deposited in 
excess of the others, and in aggravated cases to the 
exclusion of the others. Thus it is possible to deposit 
either zinc alone or copper alone from a brass solution, 
or gold alone from a nickel and gold solution. A cer- 
tain plater in New York City has recently published a 
book in which he states that no mixed solutions are 
capable of doing good, practical work for any length of 
time, a statement which has caused much amusement to 
the platers who are doing architectural work in brass 
and bronze in Chicago and other large cities, plating 
columns 15 feet long and 18 inches in diameter, panels 
36x72 inches, elevator work, etc., in bronze composed 
of copper, zinc and tin, brass plating on stove castings, 
etc. The whole secret is in the proper regulation of the 
current, both as to quantity and strength. Once the 
proper current is found, the difficulty ceases as long as 
that current is maintained. Hence, in working with 
mixed solutions the workman should have a means of 
varying the voltage and quantity of his current, and of 
reading the voltage and amperes of the current, so that 
he may compare them with his work. Volt meters and 
and ampere meters are expensive, but they will teach a 



MODERN ELECTRO PLATING. 163 

workman more about his work on mixed solutions in one 
month than he can learn otherwise in ten years. 

Necessity of Skill* In no other branch of elec- 
tro-plating is skill more necessary than in gilding or 
gold plating. While it is comparatively easy to obtain 
some kind of a gold covering on an article, it is often an 
altogether different matter to match a color or to obtain 
a thin, hard and brilliant coating that shall be durable 
without being costly. 

The Durability of gold plating does not depend alto- 
gether on the time it is in the solution. If the current 
is about two or three volts (about equal to a Bunsen 
cell, or two Smee cells connected for intensity) and the 
quantity is proportioned to the work in the bath, then 
if the solution be worked at 120 to 130 , which also 
deepens the color of the deposit, it is possible to get a 
coat inside of five minutes that will last for several 
years. 

It is always best, when other conditions are all right, 
to keep the work moving and immerse the gold anode 
sufficiently to suit the surface of the work that is being 
plated; care should be taken not to allow the work and 
anode to touch each other, as a black or burned spot 



164 MODERN ELECTRO PLATING. 

will be left on the work wherever the anode touches it. 
After getting the first slight coat of gold, the work 
should be scratch brushed with a line brass scratch brush 
(wire about .003 inch), letting a little soap suds drip on 
the brush. This lays down the first coat of gold, which 
should be sufficient to cover the article entirely. The 
scratch brush acts as a burnisher. After this it is thor- 
oughly cleaned of the soap suds in hot water, and again 
placed in the solution. The time it remains will have to 
be governed by experience, but generally five minutes 
will give a sufficient coat to stand burnishing. 

Coloring is always done with pure gold, and the best 
workmen take especial pains to see that no silver is 
allowed in the solution. They do this by using only the 
best chemicals, and frequently evaporating their baths 
and parting out the silver with nitric acid. By this 
means they obtain an immense advantage over others in 
the brightness and thinness of the coating of gold 
deposited, an advantage which shows chiefly on the 
ledger of the establishment, and in the reputation of the 
house for quick and skillful work. 

A cold solution will give a pale color; increasing the 
temperature to 140° gives a reddish color; 120 to 130 
gives a fine yellow. The reason of this is that heat 



MODERN ELECTRO PLATING. 1 65 

hastens the chemical reactions in the bath, and the gold 
deposits much more rapidly, so the operator should look 
out not to deposit more gold than he wants, and thus 
strip his solution. The anode surface should also be less 
with the hot solution. 

Finishing may be done with steel and agate burnish- 
ers, the same as with silver, or the articles may be 
polished with a soft cotton flannel buff, run at 2,500 
revolutions per minute, and bearing a very little of the 
finest rouge, mixed with alcohol. If you run your wheel 
too slow the layers of cotton will not stand up, and you 
will not get a polish; 2,500 to 3,000 revolutions is about 
right, and the pressure should be light and even. 



CHAPTER XIL 



ORMOLU FINISHES AND DIPS. 

The return of ormolu into favor and its consequent 
extended use in finishing clocks, statuettes, furniture 
trimmings, desk ornaments, paper weights, etc , is sure 
to bring with it demands upon the younger platers for a 
knowledge of this finish that they may find it extremely 
difficult to attain; consequently a short historical sketch 
may be of considerable use and interest to all who have 
spent less than twenty-five years in the business. 

Ormolu as originally produced, was a golden yellow 
alloy composed of copper, 583 parts; tin, 167 parts; 
zinc, 253 parts. The large proportion of tin gave it 
easy flowing qualities, so that very sharp castings were 
obtained. Sometimes the proportions were a little 
altered so that an excess of copper gave a reddish color 
nearly resembling that of the then popular Roman gold. 
The idea was in all cases to produce an alloy that exactly 

166 



MODERN ELECTRO PLATING. 1 67 

matched the color of the gold that was afterwards 
placed upon it, so that very little gold should be neces- 
sary to produce a durable smooth and elegant finish. In 
all cases the object was buffed bright and perfectly 
smooth, then dipped in potash, pickled and washed in 
hot water to remove all grease, and finally, fire gilt* 
Sometimes portions of the object were burnished, leav- 
ing the rest a mat surface, giving strong contrasts of 
great beauty; sometimes it was left entirely mat, giving 
a sort of half lustrous surface exceedingly soft and yet 
brilliant; and sometimes it was left a dead surface simi- 
lar to the satin finish of to-day. The second of these 
(the dull luster) was regarded with the greatest favor 
and required the most judgment to produce, as a little 
too much gold was certain to make a dead surface, while 
too little rendered the work uneven. After finishing, 
the work was lacquered, and as the fire gilding without 
burnishing gave an exceedingly open deposit, the lacquer 
penetrated deeply into it and lasted a very long time. 

The above was the original ormolu, and many speci- 
mens are still to be seen with their original lustrous soft- 
ness unimpaired by twenty-five or fifty years' use under 
glass shades or other covering. Others, originally as 
good, have had the gold rubbed off them by continuous 
dusting, or perhaps the energetic use of soap and water, 



1 68 MODERN ELECTRO PLATING. 

so that there is a dark brown stain on all the high-lights 
and large surfaces, while the less exposed parts show 
traces of their original beauty. Much of this old bric- 
a-brac will be gathered up from the garrets and brought 
to the plater, now that it is once more in fashion. 

There was also another finish called ormolu, which 
contained no gold and was inferior to it in durability, but 
had almost as much luster when new. This was much 
used in furniture, grates, andirons, and fenders, etc , of 
the cheaper class, and is now coming back with a rush. 
It is produced entirely by various dips and then lacquered 
to preserve the color thus obtained. 

In repairing or refinishing the genuine ormolu, all 
previous coatings of lacquer should be taken off, the 
object buffed bright, then dipped successively in caustic 
potash, hot water, a bright acid dip, again in hot water 
and then into the gold bath, where a very thin deposit 
of gold of just the color of the bronze used in the 
object should be laid upon it. The current should be 
regulated to give a very smooth and fine deposit, and 
one that is as bright as possible. When the coating has 
reached the color desired, it is at once removed, washed 
thoroughly in hot water and lacquered. The great 
object to be obtained is to use so little gold and have it 
so evenly distributed that the metal shall be effectually 



MODERN ELECTRO . PLATING. 1 69 

protected from tarnish without losing all of its polished 
appearance. Too much gold will give a dead or satin 
finish; too little will affect its durability. 

Ormolu Finish on brass work is usually confined 
to producing the light, bright yellow, which nearly 
approaches the color of fine gold, and we give below two 
formulas, which vary but a trifle in their composition. 
Either will do the work, but both require a little judg- 
ment to obtain the proper effects, and this can only be 
obtained by practice, as the principal knowledge 
required relates to the length of time to immerse the 
work to obtain the desired effect in the various baths. 

The work is first cleaned in the ordinary way with 
hot caustic potash; then in an ordinary cyanide dip to 
remove any stain caused by the potash; wash in hot 
water; then dip for several seconds in nitric acid, to which 
has been added ten or fifteen drops of muriatic acid per 
gallon of the nitric acid. When this acid bath is first 
made up, it is sometimes an advantage to place a piece 
of brass in it for a few minutes, to deprive it of some of 
its strength. After dipping in this, wash in clean water, 
and remove to dip No. 2, which is composed as follows: 

Nitric acid 1 pint 

Sulphuric acid 1 pint 

Sulphate of zinc (crystals) 10 ounces 



I70 MODERN ELECTRO PLATING. 

This should be well stirred before using, part of the 
zinc sulphate remaining undissolved. The work is left 
in this for three or four seconds, and washed in running 
cold water, then dipped in hot water, and dried in saw- 
dust, when it is ready for lacquering. If the color is 
not " satined " enough, repeating the dips and washings 
as above will deaden the surface still more. 

The lacquer used is generally a celluloid or other col- 
orless lacquer, with a little gold lacquer added to it to 
get the proper shade. 

The second method consists of cleaning and buffing 
as usual, then dipping in a bright dip, consisting of 

Sulphuric acid 1 gallon 

Nitric acid 3 pints 

Water 1 pint 

Common table salt, a handful. 

The object is then washed, and dipped into the ormolu 
dip which consists of 

Zinc carbonate 5 lbs. 

Sulphuric acid 15 lbs. 

Nitric acid 15 lbs. 

Pulverized saltpeter 1 X lb. 

Muriatic acid, 1 cup, little at a time. 

Care should be taken in mixing the above, as unless it 

is done slowly and carefully, there is likely to be trouble 

from the ebullition of the acids. When the dips are 



MODERN ELECTRO PLATING. 171 

properly constructed for the metal used, an instanta- 
neous immersion in the bright dip, followed by hot 
water, then the ormolu dip, and again by hot water, 
and drying in sawdust, will give the lustrous sur- 
face spoken of; repeating the operation will give a satin 
finish. 

This formula is in daily use in one of the large estab- 
lishments of this city, and gives the results with a speed 
and certainty that leaves nothing to be desired, with the 
additional advantage that almost any shade of gold may 
be given by varying the tint of the lacquer. 



CHAPTER XIIL 



BURNISHERS AND BURNISHING. 

Burnishing, while once regarded as indispensable to 
the production of a smooth, hard and durable surface, 
after plating, is gradually being given up, as the opera- 
tions of polishing and plating are better understood, 
and it is now generally acknowledged that if the work 
has been properly smoothed in the polishing room, prop- 
erly cleaned and plated with a current that will give a 
hard and tough (but not brittle) deposit, there will be no 
need of burnishing; simply buffing bright with soft 
rouge and very light pressure, will make a fine looking 
job in such a case. If the deposit is soft and spongy, 
from too strong a current in plating, or if the polishing 
or preliminary cleansing be imperfectly done, so that the 
job will not look well or wear well, matters can be con- 
siderably improved by burnishing, as it will press down 
and harden a soft deposit and smooth over rough and 
spongy places caused by imperfect cleansing or faulty 

172 



MODERN ELECTRO PLATING. 1 73 

polishing. Many things which require a bright finish 
only on certain portions while the rest of the surface is 
left mat, such as scrolls, shields and borders on hollow 
ware, or centers and margins of trays, can be more 
quickly done by burnishing than with small and thin 
buffs, particularly if the margins of the bright surface 
be formed of curves and angles, as is often the case. 

Burnishers are of two kinds, hardened steel and 
agate or bloodstone. It is usual to go over the work 
first with steel and then with stone burnishers in order 
to get a very smooth and hard surface, if the workman 
be only moderately skillful. Skilled workmen, how- 
ever, will obtain a presentable job with one operation 
and such men generally confine themselves almost 
exclusively to the use of steel burnishers, as they cost 
much less, are stronger and not so easily broken as the 
stone, and while in every day use are easily kept in 
order. 

Stone Burnishers. One point which it may be 
well to remember is that when you buy burnishers of 
agate or bloodstone you purchase them absolutely, not 
with a privilege of trial; they will not be taken back or 
exchanged for others by the dealer, nor can they be 



174 MODERN ELECTRO PLATING. 

returned if, as often happens, flaws develop during the 
first day or two of their use. The burnishers selected 
by the plater will have to be kept by him if he pur- 
chases them. The reasons for this are that the tools 
are carefully made, are subject to inspection before pur- 
chase, and are so hard that they are easily broken by a 
fall or an accidental blow while in use. Such a blow 
may start a crack in the stone, which may develop into 
a chip a week afterwards, and then the workman is 
ready to swear that it " came out of itself" under proper 
usage. These are a few of the reasons that discour- 
age the use of stone burnishers among workmen, 
although they admit the advantages of such tools over 
steel. These are superior smoothness and consequent 
ease in working, greater durability of the burnishing 
surface and less tendency to fill up with metal, and less 
loss of time spent in polishing the tool. 

Steel Burnishers* In many respects, too, the steel 
burnishers are subject to the same tendencies as the 
stone, although they vary more in texture. The closer 
grained and harder the steel becomes, the smoother it 
can be made, and the longer it will wear, and also the 
greater will be its tendency to chip or crack, for steel 
that is " glass hard " is easily broken. 



MODERN ELECTRO PLATING. I 75 

Although but little inferior to stone in the hands of a 
skilled workman, the novice is very apt to cut his work 
with steel burnishers by failing to keep the surface of 
the tool polished and free from metal, or by filling the 
tool with too hard pressure, or by holding it at such an 
angle that it will drag the surface of the work instead 
of gliding over it and pressing it down evenly and 
firmly. 

Differences in Metal. Like most other simple 
operations, burnishing is almost entirely a matter of per- 
sonal skill and proficiency, and can only be acquired by 
practice. The objects to be attained are smoothness 
and uniformity of surface and speed in producing them. 
The plating in small shops using batteries, or those 
using dynamos, in which the plater is careless or unskill- 
ful, will vary greatly in its texture. Sometimes it comes 
out soft, thick and spongy, and at others thin, close and 
so hard as to be rather brittle, varying according to the 
strength and quantity of the current and the proportions 
of cyanide and metal in the bath. The burnisher, there- 
fore, works upon varying textures of metal, and he is 
expected to largely correct the faults by burnishing all 
to a hard, durable coating, if he is doing "bright "work. 
Of course if the work is to be left mat, and only rims, 



176 MODERN ELECTRO PLATING. 

borders and escutcheons are burnished, he will be 
unable to do anything to correct the mat portions, but 
the difference will be felt on those portions which he 
does burnish. 

Method of Using, The tool is grasped firmly in 
the right hand, with the burnishing end close to the little 
finger and the forearm resting on the edge of the bench. 
Then with a firm, steady pressure, the tool is moved 
backward and forward, without taking it from the work. 
The tool is kept constantly moist by dipping it fre- 
quently in a bowl of soapsuds standing on the bench and 
it is kept polished by rubbing the burnishing surface on 
a piece of leather nailed on the bench and having a little 
tin putty or Vienna lime and oil on it. A piece of thick 
walrus or sea-horse, nailed flat, is generally used and 
by passing the burnishers over it the narrow way (as if 
you were cutting it with a knife), the tool soon makes 
itself a track that fits perfectly and thus polishes the 
whole surface at once, saving time, as a stroke or two 
on the leather covers the entire surface. Different 
widths of tools will of course have separate tracks on 
the leather. 

The tools are of different shapes to suit various 
requirements of the work, Fig. 27, and the first burnish- 



MODERN ELECTRO PLATING. 



177 




Fig. 27. —Shapes of Steel BurnisJiers. 



178 MODERN ELECTRO PLATING. 

ing is done with tools of comparatively sharp edges, 
while the finishing is done with much rounder ones, 
although, as the workman acquires skill, he will go over 
his work less and use fewer tools, gradually settling 
down to a few forms which he finds best suited to his 
run of work. 

Brittle deposits must have just sufficient pressure to 
smooth the work; coarse and spongy metal needs harder 
pressure. Caution must be exercised in inspecting the 
work before beginning to burnish, as unless it is known 
to be all right, the metal may be stripped off from faulty 
places in the work by too much pressure, and this is 
pretty sure to be followed by a quarrel between the bur- 
nisher and plater. The former maintains that the work 
was not properly plated and the plater alleges that it 
would have stood all right if the burnisher had not 
stripped it through carelessness. In any case the work 
has to be done over. 



CHAPTER XIV. 



SOME FINISHES FOR PLATERS. 

One of the most vexatious questions that annoy the 
average plater is that of finishing or "coloring" his 
work. I was in a supply store recently and overheard 
a customer say to the salesman. "That silver solution 
you sent me isn't right at all. I want black silver. 
This plates all right, but is as white as the pure metal, 
and I want that black silver that is seen everywhere 
now-a-days." The salesman seemed to regard the pro- 
test as an everyday affair, and calmly explained that the 
black color was produced afterward, giving some simple 
directions, and he departed apparently satisfied and cer- 
tainly wiser. 

This set me to thinking, and after overhauling a lot of 
old formulas, containing almost everything from bills 
and livers of ducks to chloride of gold and platinum, I 
began to wonder how many of those who used those 
recipes realized what they were doing, and it occurred 

179 



l8o MODERN ELECTRO PLATING. 

to me that perhaps a few plain words on the chemistry 
of these finishes might be of service to the younger 
generation of platers. In the first place it will be evi- 
dent that all these mysteriously compounded recipes are 
simply intended to tarnish the bright metal. Now, 
most of the colored compounds on silver, copper and 
brass consist either of sulphides, chlorides or carbides; 
that is, of a union of sulphur, chlorine or carbon with 
the metal upon which the discoloration is to be pro- 
duced. This being clear, it follows that we must use 
those compounds in our dips which have the sulphur or 
chlorine held in very feeble union with the base, so that 
it will readily part from that base and unite with the 
bright metal when it is dipped into the solution. This 
is practically all that there is to the dip, and it will be 
readily seen that the vast quantity of stuff put into many 
of the recipes is utterly useless, in fact, worse than use- 
less, most of them being a positive detriment. 

One of the compounds most generally used is the 
pentasulphide of potassium (liver of sulphur). It parts 
readily with its sulphur, and the potassium being left 
free in the solution, attracts oxygen first, then carbonic 
acid from the air, and thus becomes caustic potash, 
which is too well known as a cleansing agent in the 
plating room to need further comment. 



MODERN ELECTRO PLATING. 1 01 

A solution of one ounce of liver of sulphur to the 
gallon of water should be made up and allowed to stand 
over night, when it will be ready for use with either 
silver, copper, bronze or brass. The next requisite is to 
obtain a surface on the metal that will take the sulphur 
evenly. This is done by exercising the utmost care in 
regard to cleanliness. If the color is uneven, light in 
some places and dark in others, or filled with dark spots, 
or light spots, you can decide that the metal is not clean 
when it is dipped. The work is cleaned as for plating, 
and then brushed with powdered pumice stone evenly 
all over, rinsed in hot water, and then dipped in the 
liver of sulphur and allowed to remain until the right 
color is reached, when it is removed, dipped in hot 
water, dried, and lacquered. 

This brings us to the question of color, which depends 
altogether upon the strength of solution and the length 
of time the work remains in it. An instantaneous dip 
will result in a gray color on silver, and it gradually 
deepens as the time is increased, until the metal is entirely 
hidden. Midway between these are any quantity of 
semi-transparent shades of great beauty. With copper, 
tones can be obtained ranging from an ochre color to 
deep black, according to the depth or transparency of 
the deposit. Brass can also be similarly shaded. The 



1 82 MODERN ELECTRO PLATING. 

strength of the solution given above is suitable for all but 
the lightest shades; for these it is advisable to add more 
water. The workman will see that there is a large 
margin left him for taste and skill in using these dips, as 
is always the case in simple operations, and if he will 
patiently learn how to do them, by experimenting with 
the various metals, he will be well repaid for his time 
and trouble. 

One of the most useful dips for platers, next to the 
liver of sulphur, mentioned above, is the green. This is 
generally used on brass, more rarely on copper and 
silver, and frequently on zinc. The same rules as to 
cleanliness of the object and the length of immersions, 
washings, etc., apply to all these dips, and it will be 
understood without mentioning them in future. 

Green, Red or Brown Bronze for Brass is fre- 
quently used on statuettes, either of brass or copper, 
builder's hardware, etc., and is composed of 

Hyposulphite of sodium 4 ounces. 

Nitrate of iron 4 ounces 

Water 1 quart. 

Dissolve the iron and soda in the water, and allow 
to stand until thoroughly incorporated. Then dip the 
article as previously described. On being immersed 



MODERN ELECTRO PLATING. 1 83 

the article turns brown, then red, and finally green, so 
that it will readily be perceived that any number of 
shades can be produced with this dip. 

Olive Green on Brass is made by immersing in 

Perchloride of iron 1 part by weight. 

Water 2 parts by weight. 

This dip produces green tints ranging from a pale to 
a dark olive green on brass, according to the time of 
immersion. The articles, after being buffed, should 
have all grease removed by being dipped in hot potash, 
then in hot water, then in a solution of cyanide, made 
up of one-half pound of cyanide of potassium to each 
gallon of water, and finally immersed in the green dip. 
If the color is uneven, the treatment with pumice stone 
previously described must be applied. 

Frequently articles brought in to be repaired or 
cleaned up are from some cause, such as worn plating, 
etc., unsuitable for dipping, as the color would be very 
uneven, while it would not pay to strip and replate. In 
such cases the color is applied in the finishing lacquer; 

Green Patina on any MetaL Carbonate of cop- 
per, or verdigris, or any suitable mixture of the two 
salts, according to the tint desired, is mixed in zapon 



184 MODERN ELECTRO PLATING. 

lacquer, or any light colored varnish, and applied to the 
object with a brush, and the high parts immediately 
wiped off with a rag dipped in the proper solvent for 
the varnish. If zapon or other celluloid lacquer be 
employed, the rag should be dipped in " lacquer 
thinner " (acetate of amyl) ; if an alcoholic varnish 
be used, then, of course, alcohol should be used on the 
wiping rag. It takes a little experience to get the nec- 
essary touch to leave a smooth and even coating on the 
object; when this is once acquired, however, the work 
is accomplished as quickly as plain lacquering, and can, 
of course; be used on any metal. A final coat of clear 
lacquer should be given after the bronzing coat is dry, 
to protect the bare parts of the metal from oxidation. 

Light Green on Sheet Zinc* A very nice light 
green may be imparted to sheet zinc by means of the 
following: Dissolve 10 parts of hyposulphite of sodium 
in 100 parts of water in a well glazed stone crock or a 
glass jar and then add to it slowly, with constant stir- 
ring, 5 parts of sulphuric acid. The liquid will become 
hot by the addition of the sulphuric acid, and it should 
be allowed to cool until the milk of sulphur settles in 
powder or lumps at the bottom. Decant the liquid con- 
taining sulphate of sodium and sulphurous acid and 



MODERN ELECTRO PLATING. 1 85 

place the zinc articles into the same, after being heated 
to at least 15 Fah. A light green will be produced in 
a short time. Wash, dry and lacquer. The work must 
in all cases be clean and free of grease. The better 
the polish the more brilliant the resulting color. 

Mat or Matte Silver Finish on Thermometer 
Scales, Clock Dials, Etc* Heat the articles, if they 
have no soft soldered parts about them, in an alcohol 
flame or Bunsen burner, and plunge them while hot into 
a cold pickle of 100 parts water and 10 parts sulphuric 
acid, previously prepared by pouring the sulphuric acid 
slowly into the water while stirring. Rinse off the 
articles, dry and lacquer. Never pour water into acid- 
Pink on Silver* Pinkish colorations on silver sur- 
faces are produced by immersing the articles for a few 
seconds in a hot concentrated solution of chloride of 
copper; wash well in water, dry and lacquer. Where 
there are copper plating solutions and electric current at 
hand (battery or dynamo), a still better result can be 
obtained by giving the articles just a flash of copper in 
a sulphate of copper solution, and upon this rose col- 
ored deposit a thin coating of silver in a cyanide of sil- 
ver solution, and thus blend these two deposits. 



CHAPTER XV. 



THE METHODS OF USING LACQUERS. 

With the exception of nickel and gold, all the work 
turned out by the plater is greatly improved in appear- 
ance and the durability of the final polish by having one 
or more coats of lacquer applied to it before delivery to 
the customer. In the case of easily tarnished metals, 
such as brass or copper, and when the final color has 
been produced by dipping, this is a necessity. 

The oldest lacquers were simply transparent var- 
nishes, generally of shellac and alcohol, applied very 
thin and repeated two or three times to get the neces- 
sary thickness and perfectly cover the metal. With the 
invention of celluloid and its application to so many 
articles of ornament and use, came the death blow to 
the gum lacquers, as it was speedily found that celluloid 
could be dissolved in acetate of amyl and acetone and, 
thus prepared, made a harder, tougher, more transpar- 
ent, more durable and cheaper lacquer than any of the 



MODERN ELECTRO PLATING. 1 87 

combinations of gum and alcohol or other solvents. It 
is more easily handled, can be colored more readily, and 
is the only colorless lacquer, and therefore the only one 
perfectly adapted to silverware. 

The celluloid lacquer is sold in the market under var- 
ious names, but may be classified under two general 
heads, colorless and colored. They are largely sold in 
various grades, adapted for special purposes, and if the 
plater is doing a special line of work he will find it 
most economical to buy his lacquer as specially pre- 
pared for that work. Those doing a large variety of 
work, or desiring to experiment, will find it of advan- 
tage to buy colorless lacquer, colors and "lacquer 
thinner " and mix colors to suit themselves. Lacquer 
colors are specially prepared and are sold in a concen- 
trated form, so that the novice must be very careful not 
to get in too much. They dissolve readily in the lac- 
quer, but do not become evenly distributed throughout 
the whole of the fluid for some hours, so that care must 
be taken to mix them the day before they are to be 
used, if more than a few ounces of a special color are 
to be made up. 

Large establishments have a room (free from dust) 
heated to I40°F. and provided with a chimney or other 
means of draught to carry off the fumes of the acetone, 



I OO MODERN ELECTRO PLATING. 

which are disagreeable to many persons. The lacquer 
is placed in a wooden or enameled iron vat, and the 
articles, perfectly clean and warmed to ioo° or no°F., 
are hung on hooks and dipped into the vat. taken out, 
turned about a moment to allow the superfluous liquid 
to run off, and hung up to dry. The lacquer thickens 
up in use and must be diluted from time to time with 
the "thinner." If too thick, the work is uneven; if too 
thin, rainbow colors show on the article and it must be 
dipped again. 

Articles which cannot be hung up are generally dried 
in trays having bottoms made of wire cloth; a rather 
coarse mesh is used and the trays are stacked up over 
the source of heat, after the articles have ceased to 
drip. In this way great numbers of small articles may 
be handled in very little space, and may be left in the 
drying room long enough to become thoroughly hard, 
which is the chief point as regards durability of the 
lacquer. 

Small establishments generally use a sheet iron drum 
or oven, which may be heated by gas or an oil stove to 
the degree required to bake the lacquer properly. To 
warm the articles they use a " hot plate," or an iron 
tray placed over a gas stove. Many small shops do 
their drying on wire trays resting on a steam coil, when 



MODERN ELECTRO PLATING. 1 89 

they can get steam the year round. The reader will 
perceive that the proper degree of heat is the main 
thing and that he can use his option as to applying it. 

Brush lacquer is the same as dip lacquer, except that 
it is of thicker body, so as to spread well under the 
brush. A small portion at a time is turned out in a 
shallow pan or cup and applied with fitch or camel hair 
brushes, as rapidly and evenly as possible to the warmed 
article, which is then put in the drying oven and dried 
as for dip lacquer. Any little unevenness in the work 
will disappear in the oven, but considerable care and 
dexterity are needed to make a really nice job. For 
this reason most of the lacquering is done by girls, who 
do nothing else, and necessarily become expert at it. 
Nearly all special colors are applied with the brush and 
many of the most attractive finishes owe as much to the 
lacquer as to the dip, as the former in many cases lends 
transparent beauty to what would otherwise be a dull 
and prosaic color 

Great care must be taken to keep the lacquer away 
from all sources of moisture or grease, as either will 
cause white spotson the finished work. Lacquer will 
attract moisture from the air if allowed to stand in a 
damp room and much trouble has frequently been 
caused by neglect of this precaution. 



INDEX. 



PAGE. 

Acid, boracic ._ 119 

Alloys, effects of current strength 

on 161 

Amalgamating zinc 24 

Ampere 9 

" meter 40 

Amounts of silver deposited 136 

Anodes for brass 105 

" copper 106 

" nickel 110 

" silver 132 

Aqua regia 144 

Arsenic, to dissolve 122 



Balancing wheels 66 

Battery, Bunsen 18 

Daniel 13 

" gravity 15 

" Smee 19 

Batteries coupling 22 

" management of 7 

selection of 12 

Belt straps 65 

Black nickel plating 121 

Boracic acid 119 

Brass baths 98, 100 

" " management of 101 

" dip for 83 

" olive green, for 183 

" pickle for 82 

" polishing 78 

Bright Gilding 157 

Britannia, to polish 78 

Bronze, brown for brass 182 

" green on brass 182 

" green on zinc 184 

" pink on silver 185 

" red on brass 182 

Brushes 72 

" scratch 74 

Buffs, cotton 63 



PAGE. 

Buff stick 61 

Bull neck wheels 62 

Burnishing, effects of 172 

Burnishers 173 

steel 174 

" stone 173 

" method of using 176 

" shapes of 177 

Boxes, tumbling 54 



Canvas wheels 58 

Carat solutions 157 

Chloride of gold 144 

" per centage of gold in 146 

" of silver 128 

Coloring with gold lf>4 

" in polishing 65 

" wheels 65 

Connections 26, 33 

Copper baths 98, 103 

" " management of.. 101, 105 

Copper, dip for 83 

pickle for 82 

" to polish 78 

Corundum wheels 57 

Cotton buffs 63 

Coupling batteries 22 

Crocus 71 

Current, regulation of 

22,37, 90, 101, 105, 112, 131, 139, 142, 152 

Current strength for alloys 161 

" " " brass 101 

" " " copper 105 

" gold 142, 152 

" nickel 112 

" silver— .131,139 

Cyanide dip for brass 83 

Cyanide of potassium in brass 

baths 101 

Cyanide of potassium in copper 

baths 101,104 

Cyanide of potassium in gold baths 147 
" " " in silver baths, 
130,138 



INDEX. 



PAGE. 

Dips and pickles, action of 80 

Dip for copper or brass 83 

" cyanide for brass 83 

" ormolu 169 

Dynamos, care of 32 

" connections for 33 

" requirements of 31 

use of 28, 30 



Electricity, definition of 8 

Electropoion fluid 25 

Emery wheels 57 



PAGE. 

Instruments, measuring 38 

Iron, pickle for 82 

" and steel to polish 76 



Lacquering 186 

Lead, to polish 78 

Leather wheels 61 

Lime, Vienna 72 

Lining tanks 42 

Liver of sulphur 181 



M 



Felt wheels. 62 

Flexible shaft 51 

Finishing gold 165 

nickel 120 

black nickel 126 

Finishes for platers 179 

" ormolu 169 



German silver, pickle for 83 

Gold 141 

" alloys, pickles for 84 

" baths, temperature of 148.155 

" chloride of 144 

" to dissolve 144 

" to strip 92 

" plating, durability of 163 

" solutions, color of 142.148,155 

hot ....148 

cold 151 

" for bright gilding. .157 

for iron and steel -156 

" containing nickel.. 160 

" carat 157 

" green 159 

pale 159 

red 158 

rose 158 

" " stock... 149 

Grease wheels 64 

Green bronze for brass 182 

" light on zinc 184 

" patina on any metal 183 

" to remove 92 



Management of batteries 7 

Machinery for polishing. 49 

Materials forpolishing 69 

Measuring instruments 38 



N 



Nickel and gold solutions 160 

black plating 121 

" deposits, faults in 116,118 

solutions 109, 124 

" " appearance of 113 

" " condition of 113 

to polish 120 

tostrip 91 



Olive green on brass 183 

Ormolu dips 169 

" finishes... 166 

Oxides, to strip 92 



Pale gold solutions 159 

Patina on any metal 184 

Pickle for brass 82 

" black for iron 82 

" bright for iron 82 

" copper 82 

" german silver 83 

" gold alloys 84 



INDEX. 



PAGE. 

Pink on silver - 185 

Polishing, direction of 68 

heads 50,52 

" materials 69 

'' room, machinery of. -49 

" , " ventilation of 49 

Polishing wheel cleaner 60 

" " wood 59 

Polishing brass 78 

" britannia 78 

" copper .78 

" iron and steel 76 

lead 78 

nickel 120 

tin 78 

" zinc 78 

Preparation of work 76 

Proportions of metal in salts 161 

Pumice stone 73 



Quicking solutions 95 



Rattling boxes 54 

Red bronze on brass 182 

Red gold solutions 158 

Regulation of current 

..22, 37, 101, 105, 112, 131, 139, 142, 152 

Removing green 92 

Resistance, electrical.. 10 

" switch 37 

Rose colored gold solutions 159 

Rouge 71 



Scratch brushes 74 

Scouring sink 73 

Sectional plating 137 

Shaft, flexible.- 51 

Shapes of steel burnishers 177 

Silver chloride 128 

cyanide 138 

Silver solutions 127, 130, 137 

Silver, amounts deposited ...136 

" solutions, management of 131, 133 

" " work and anodes in, 132 
Silver plating, cheap work.- 95 

" pink on 185 

to strip 91 

Sink, scouring - :.-- 73 

Speed of scratch brushes 74 

" " wheels 67 



PAGE. 

Steel burnishers, shapes of 177 

Straps, belt 65 

Striking solution 133 

Stripping solutions, use of 89 

gold - 92 

nickel 91 

" oxides r 92 

" silver 91 

" solutions, use of 89 

Sulphur, liver of ...181 

Switch, resistance 37 



Tanks, capacity of.- 43 

" heating 44 

" iron 43 

" lining 42 

" plating - 41 

" small 43 

Temperature of gold solutions. 148, 155 

" nickel " 118 

Tin, to polish 78 

Tripoli 71 

Tumbling boxes 54 

Turning yellow 137 

V 

Ventilation of polishing room 49 

Vienna lime 72 

Voltage 8 

Voltmeter 39 

w 

Wheels, balancing 66 

bull neck 62 

" canvas 58 

" cleaner 60 

" emery or corundum 57 

felt 62 

" grease 64 

leather 61 

" speed of 67 

" walrus 61 

" wood polishing 59 

Wire, electrical capacity of 27 

Work, preparation of 76 

Z 

Zinc, to amalgamate 24 

" light green for 184 

" to polish 78 



Particular Attention is nailed to the Celebrated Imperial Mainsprings, 

Every day we receive the most flattering, unsolicited testi- 



monials, samples of which we 
submit as follows : 

Coshocton, O., Aug. 8, 1896. 
Messrs. Green Bros., New York. 

Gentlemen -.—Enclosed please find 
check in payment of Cabinet of Imperial 
•Maitosp rings less cash discount. Your 
'springs are, beyond doubt, the finest 
; finrs'hed and most reliable in the market. 
We are very well pleased with them, 
-also the handsome cabinet. 

Very respectfully, 

Burns & Gosser. 



54 and 56 Seneca Street, 
Buffalo, N. Y., March 2, 1896. 
Messrs. Green Bros., New York. 

Dear Sirs:— We have been using your 
Imperial Mainsprings for some time 
and can say for them, I think they are 
the best springs I ever used. The finish 
and make are good and their durability 
unexcelled by even the higher priced 
springs. Should prefer them to any 
spring I ever used. 

Respectfully, 

Frank Hammond, 

Watch Inspector and Adjuster for N. Y , L. E. & 
W. R. R.; L. S. & M. S. R. R.; L. V. R. R.; 
B. R. &P. R. R. 



Registered Trade Mark and Fac Simile of Wrapper en our Imperial American Mainsprings. 




The Imperial Mainsprings are guaranteed for one y eat. 
Each Spring bears the Word " IMPERIAL." 

Each Sprang is tagged with the Name and Size; for Finish, Temper, 
Elasticity and Durability they have no equal. 

price : 
$12.00 PER GROSS. 

Exact cut of the Imperial Spring, 1.00 PER DOZEN. 

coiled and tagged. 

GREEN BROS. 

6 MAIDEN LANE, ••• NEW YORK. 

IMPORTERS AND JOBBERS OF.... 

Fine Grade Watcn materials, Tools and Jewelers' General Supplies. 

If you want good and Quick Service and Genuine American Watch Material, send 
us a Trial Order. Orders filled from .any catalogue. 





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Polishers' Supplies. 



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WE FURNISH EVERYTHING 



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Prize Essay on Watch Cleaning and Eepairing. By F. C. Ries. This work 
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